Tuesday, May 29, 2018

CBSE PORTAL : (Result) CBSE - Class X Examination Result 2018

CBSE PORTAL : (Result) CBSE - Class X Examination Result 2018

Link to CBSE PORTAL : CBSE, ICSE, NIOS, JEE-MAIN, AIPMT Students Community

(Result) CBSE - Class X Examination Result 2018

Posted: 29 May 2018 01:04 AM PDT

(Result) CBSE - Class X Examination Result 2018

Exam Name: CBSE

Class: 10th

Year: 2018

Date of Result Declaration : 29th May, 2018

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Courtesy: CBSE

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(Download) CBSE Class-12 Sample Paper And Marking Scheme 2017-18 : Psychology

Posted: 29 May 2018 12:22 AM PDT

(Download) CBSE Class-12 Sample Paper And Marking Scheme 2017-18 : Psychology

Psychology
Class- XII
Sample Question Paper – 2018

Time – 3 Hours

Max Marks – 70

General instructions

  • All questions are compulsory and answers should be brief and to the point.
  • Marks for each question are indicated against it.
  • Question No 1- 10 in part A are multiple choice questions carrying 1 mark each. You are expected to answer them as directed.
  • Question No 11-16 in Part B are very short answer questions carriying2 marks each. Answer to each question should not exceed 30 words.
  • Question No. 17-20 in Part C are short answer type-I questions carrying 3 marks each. Answer to each question should not exceed 60 words.
  • Question No. 21-26 in Part D are short answer type-II questions carrying 4 marks each. Answer to each question should not exceed 100 words.
  • Question No. 27 and 28 in Part E are long answer type questions carrying 6 marks each. Answer to each question should not exceed 200 words.

Part – A

Q 1. Ritu is hardworking, committed and patiently works towards her
goal. She is said to be high on ––––––– competence.
a) Cognitive
c) Emotional
b) Entrepreneurial
d) Social
Q 2. An individual is rejected in a job interview, which he was very
eager to join. Now he claims his present job is better. He is
using__________:
a) Reaction Formation
b) Projection
c) Regression
d) Rationalisation
Q 3. The impact of any stressful event depends largely on the way we
interpret it. (True /False)
Q 4. A student thinks that he can complete the task effectively and achieve his goal. This is an example of:
a) Self efficacy
b) Self esteem
c) Self concept
d) Self control
Q 5. Sunil shows loss of interest in most of the activities, cannot sleep well at night, exhibits excessive guilt and loss of interest in activities that he would enjoy earlier. Sunil’s symptoms are akin to that of:
a) Somatoform Disorder c) Major depressive disorder
b) Obsessive compulsive disorder d) Generalised Anxiety Disorder
Q 6. The therapy that leads to cognitive restructuring has proved to be successful in the treatment of _______________________.
a) Depression and mania
b) Schizophrenia
c) Phobias
d) Anxiety and depression
Q7. When an individual changes in a direction opposite to the existing attitude, it is called incongruent attitude change (True/ False)

Q 8. Values refer to the cognitive component of attitudes, and form the ground on which attitudes stand, like belief in the Supreme Being. (True/ False)
Q 9. ‘Perceiving or thinking that one has got less than what one should get’ refers to __________.
Q 10. A ____________ is a purposeful conversation between two or more people that follows a basic question and answer format.

Part – B

Q 11. What are the characteristics that comprise positive health?
Q. 12. Differentiate between surface and source traits.

Click Here To Download Full Sample Paper

Click Here To Download Full Marking Scheme

CBSE (Class XII) Previous Year Papers Printed Books

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NCERT Mathematics Question Paper (Class - 9)

Posted: 29 May 2018 12:15 AM PDT

NCERT Mathematics Question Paper (Class - 9)

 


(Mathematics) Chapter 3 Coordinate Geometry


EXERCISE 3.1 

Question 1. How will you describe the position of a table lamp on your study table to another person?

Question 2. (Street Plan) : A city has two main roads which cross each other at the centre of the city. These two roads are along the North-South direction and East-West direction.

(i) The perpendicular distance of the point P from the y - axis measured along the positive direction of the x - axis is PN = OM = 4 units.
(ii) The perpendicular distance of the point P from the x - axis measured along the positive direction of the y - axis is PM = ON = 3 units.
(iii) The perpendicular distance of the point Q from the y - axis measured along the negative direction of the x - axis is OR = SQ = 6 units.
(iv) The perpendicular distance of the point Q from the x - axis measured along the negative direction of the y - axis is OS = RQ = 2 units. Now, using these distances, how can we describe the points so that there is no confusion? We write the coordinates of a point, using the following conventions:

(i) The x - coordinate of a point is its perpendicular distance from the y - axis measured along the x -axis (positive along the positive direction of the x - axis and negative along the negative direction of the x - axis). For the point P, it is + 4 and for Q, it is – 6. The x - coordinate is also called the abscissa.
(ii) The y - coordinate of a point is its perpendicular distance from the x - axis measured along the y - axis (positive along the positive direction of the y - axis and negative along the negative direction of the y - axis). For the point P, it is + 3 and for Q, it is –2. The y - coordinate is also called the ordinate.
(iii) In stating the coordinates of a point in the coordinate plane, the x - coordinate comes first, and then the y - coordinate. We place the coordinates in brackets. Hence, the coordinates of P are (4, 3) and the coordinates of Q are (– 6, – 2). Note that the coordinates describe a point in the plane uniquely. (3, 4) is not the same as (4, 3).

EXERCISE 3.2

Question 1.Write the answer of each of the following questions:

(i) What is the name of horizontal and the vertical lines drawn to determine the position of any point in the Cartesian plane?
(ii) What is the name of each part of the plane formed by these two lines?
(iii) Write the name of the point where these two lines intersect.

Questions 2. See Fig.3.14, and write the following:

(i) The coordinates of B.
(ii) The coordinates of C.
(iii) The point identified by the coordinates (–3, –5).
(iv) The point identified by the coordinates (2, – 4).
(v) The abscissa of the point D.
(vi) The ordinate of the point H.
(vii) The coordinates of the point L.
(viii) The coordinates of the point M.


(Mathematics) Chapter 4 Linear Equations in Two Variables


EXERCISE 4.1

Question 1. The cost of a notebook is twice the cost of a pen. Write a linear equation in two variables to represent this statement. (Take the cost of a notebook to be Rs x and that of a pen to be Rs y).

Question 2. Express the following linear equations in the form ax + by + c = 0 and indicate the values of a, b and c in each case:

(i) 2x + 3y = 9.35
(ii) x – 5 y – 10 = 0
(iii) –2x + 3y = 6
(iv) x = 3y
(v) 2x = –5y (
vi) 3x + 2 = 0
(vii) y – 2 = 0
(viii) 5 = 2x

EXERCISE 4.2

Question 1.Which one of the following options is true, and why? y = 3x + 5 has

(i) a unique solution
(ii) only two solutions
(iii) infinitely many solutions

Question 2. Write four solutions for each of the following equations:

(i) 2x + y = 7
(ii) πx + y = 9
(iii) x = 4y

Question 3. Check which of the following are solutions of the equation x – 2y = 4 and which are not:

(i) (0, 2)
(ii) (2, 0)
(iii) (4, 0)
(iv) ( 2 , 4 2)
(v) (1, 1)

Question 4. Find the value of k, if x = 2, y = 1 is a solution of the equation 2x + 3y = k.

EXERCISE 4.3

Question 1. Draw the graph of eachof the following linear equations in two variables:

(i) x + y = 4
(ii) x – y = 2
(iii) y = 3x
(iv) 3 = 2x + y

Question 2. Give the equations of two lines passing through (2, 14). How many more such lines are there, and why?

Question 3. If the point (3, 4) lies on the graph of the equation 3y = ax + 7, find the value of a.


Question 4. The taxi fare in a city is as follows: For the first kilometre, the fare is Rs 8 and for the subsequent distance it is Rs 5 per km. Taking the distance covered as x km and total fare as Rs y, write a linear equation for this information, and draw its graph.

Question 5. From the choices given below, choose the equation whose graphs are given in Fig. 4.6 and Fig. 4.7. For Fig. 4. 6 For Fig. 4.7

(i) y = x
(i) y = x + 2
(ii) x + y = 0
(ii) y = x – 2
(iii) y = 2x
(iii) y = –x + 2
(iv) 2 + 3y = 7x
(iv) x + 2y = 6

Question 6. If the work done by a body on application of a constant force is directly proportional to the distance travelled by the body, express this in the form of an equation in two variables and draw the graph of the same by taking the constant force as 5 units. Also read from the graph the work done when the distance travelled by the body is (i) 2 units (ii) 0 unit

Question 7. Yamini and Fatima, two students of Class IX of a school, together contributed Rs 100 towards the Prime Minister's Relief Fund to help the earthquake victims. Write a linear equation which satisfies this data. (You may take their contributions as Rs x and Rs y.) Draw the graph of the same.

Question 8. In countries like USA and Canada, temperature is measured in Fahrenheit, whereas in countries like India, it is measured in Celsius. Here is a linear equation that converts Fahrenheit to Celsius: F = 9 C + 32 5

(i) Draw the graph of the linear equation above using Celsius for x-axis and Fahrenheit for y-axis.
(ii) If the temperature is 30°C, what is the temperature in Fahrenheit?
(iii) If the temperature is 95°F, what is the temperature in Celsius?
(iv) If the temperature is 0°C, what is the temperature in Fahrenheit and if the temperature is 0°F, what is the temperature in Celsius?
(v) Is there a temperature which is numerically the same in both Fahrenheit and Celsius? If yes, find it.

EXERCISE 4.4

Question 1. Give the geometric representations of y = 3 as an equation

(i) in one variable
(ii) in two variables

Question 2. Give the geometric representations of 2x + 9 = 0 as an equation

(i) in one variable
(ii) in two variables


(Mathematics) Chapter 7 Triangles


EXERCISE 7.1

Question 1. In quadrilateral ACBD, AC = AD and AB bisects ∠ A (see Fig. 7.16). Show that Δ ABC Δ ABD. What can you say about BC and BD?

Question 2 . ABCD is a quadrilateral in which AD = BC and ∠ DAB = ∠ CBA (see Fig. 7.17). Prove that

(i) Δ ABD Δ BAC
(ii) BD = AC
(iii) ∠ ABD = ∠ BAC.

Question 3. AD and BC are equal perpendiculars to a line segment AB (see Fig. 7.18). Show that CD bisects AB.

Question 4. l and m are two parallel lines intersected by another pair of parallel lines p and q (see Fig. 7.19). Show that Δ ABC Δ CDA.

Question 5. line l is the bisector of an angle ∠ A and B is any point on l. BP and BQ are perpendiculars from B to the arms of ∠ A (see Fig. 7.20). Show that:

(i) Δ APB Δ AQB
(ii) BP = BQ or B is equidistant from the arms of ∠ A.

Question 6. In Fig. 7.21, AC = AE, AB = AD and ∠ BAD = ∠ EAC. Show that BC = DE.

Question 7 . AB is a line segment and P is its mid-point. D and E are points on the same side of AB such that ∠ BAD = ∠ ABE and ∠ EPA = ∠ DPB (see Fig. 7.22). Show that

(i) Δ DAP Δ EBP
(ii) AD = BE

Question 8. In right triangle ABC, right angled at C, M is the mid-point of hypotenuse AB. C is joined to M and produced to a point D such that DM = CM. Point D is joined to point B (see Fig. 7.23). Show that:

(i) Δ AMC Δ BMD
(ii) ∠ DBC is a right angle.
(iii) Δ DBC Δ ACB
(iv) CM = 1 2 AB

EXERCISE 7.2

Question 1. In an isosceles triangle ABC, with AB = AC, the bisectors of ∠ B and ∠ C intersect each other at O. Join A to O. Show that :

(i) OB = OC
(ii) AO bisects ∠ A

Question 2. In Δ ABC, AD is the perpendicular bisector of BC (see Fig. 7.30). Show that Δ ABC is an isosceles triangle in which AB = AC.

Question 3. ABC is an isosceles triangle in which altitudes BE and CF are drawn to equal sides AC and AB respectively (see Fig. 7.31). Show that these altitudes are equal.

Question 4. ABC is a triangle in which altitudes BE and CF to sides AC and AB are equal (see Fig. 7.32). Show that

(i) Δ ABE Δ ACF
(ii) AB = AC, i.e., ABC is an isosceles triangle.

Question 5. ABC and DBC are two isosceles triangles on the same base BC (see Fig. 7.33). Show that ∠ ABD = ∠ ACD.

Question 6. ΔABC is an isosceles triangle in which AB = AC. Side BA is produced to D such that AD = AB (see Fig. 7.34). Show that ∠ BCD is a right angle. 7. ABC is a right angled triangle in which ∠ A = 90° and AB = AC. Find ∠ B and ∠ C.

Question 7. Show that the angles of an equilateral triangle are 60°each.

EXERCISE 7.3

Question 1. Δ ABC and Δ DBC are two isosceles triangles on the same base BC and vertices A and D are on the same side of BC (see Fig. 7.39). If AD is extended to intersect BC at P, show that

(i) Δ ABD Δ ACD
(ii) Δ ABP Δ ACP
(iii) AP bisects ∠ A as well as ∠ D.
(iv) AP is the perpendicular bisector of BC.

Question 2. AD is an altitude of an isosceles triangle ABC in which AB = AC. Show that

(i) AD bisects BC
(ii) AD bisects ∠ A.

Question 3. Two sides AB and BC and median AM of one triangle ABC are respectively equal to sides PQ and QR and median PN of Δ PQR (see Fig. 7.40). Show that:

(i) Δ ABM Δ PQN
(ii) Δ ABC Δ PQR

Question 4.
BE and CF are two equal altitudes of a triangle ABC. Using RHS congruence rule, prove that the triangle ABC is isosceles.

Question 5. ABC is an isosceles triangle with AB = AC. Draw AP ⊥ BC to show that ∠ B = ∠ C.

EXERCISE 7.4

Question 1. Show that in a right angled triangle, the hypotenuse is the longest side.

Question 2. In Fig. 7.48, sides AB and AC of Δ ABC are extended to points P and Q respectively. Also, ∠ PBC < ∠ QCB. Show that AC > AB. 3. In Fig. 7.49, ∠ B < ∠ A and ∠ C < ∠ D. Show that AD < BC.

Question 3. AB and CD are respectively the smallest and longest sides of a quadrilateral ABCD (see Fig. 7.50). Show that ∠ A > ∠ C and ∠ B > ∠ D.

Question 4. In Fig 7.51, PR > PQ and PS bisects ∠ QPR. Prove that ∠ PSR > ∠ PSQ.

Question 5. Show that of all line segments drawn from a given point not on it, the perpendicular line segment is the shortest.

EXERCISE 7.5

Question 1 . ABC is a triangle. Locate a point in the interior of Δ ABC which is equidistant from all the vertices of Δ ABC.

Question 2. In a triangle locate a point in its interior which is equidistant from all the sides of the triangle.

Question 3. In a huge park, people are concentrated at three points (see Fig. 7.52):

A : where there are different slides and swings for children,
B : near which a man-made lake is situated,
C : which is near to a large parking and exit. Where should an icecream parlour be set up so that maximum number of persons can approach it? (Hint : The parlour should be equidistant from A, B and C)

Question 4. Complete the hexagonal and star shaped Rangolies [see Fig. 7.53(i) and (ii)] by filling them with as many equilateral triangles of side 1 cm as you can. Count the number of triangles in each case. Which has more triangles?


(Mathematics) Chapter 8 Quadrilaterals


EXERCISE 8.1

Question 1. The angles of quadrilateral are in the ratio 3 : 5 : 9 : 13. Find all the angles of the quadrilateral.

Question 2. If the diagonals of a parallelogram are equal, then show that it is a rectangle.

Question 3. Show that if the diagonals of a quadrilateral bisect each other at right angles, then it is a rhombus.

Question 4. Show that the diagonals of a square are equal and bisect each other at right angles.

Question 5. Show that if the diagonals of a quadrilateral are equal and bisect each other at right angles, then it is a square.

Question 6. Diagonal AC of a parallelogram ABCD bisects ∠ A (see Fig. 8.19). Show that

(i) it bisects ∠ C also
(ii) ABCD is a rhombus.

Question 7. ABCD is a rhombus. Show that diagonal AC bisects ∠ A as well as ∠ C and diagonal BD bisects ∠ B as well as ∠ D.

Question 8. ABCD is a rectangle in which diagonal AC bisects ∠ A as well as ∠ C. Show that:

(i) ABCD is a square
(ii) diagonal BD bisects ∠ B as well as ∠ D.

Question 9. In parallelogram ABCD, two points P and Q are taken on diagonal BD such that DP = BQ (see Fig. 8.20). Show that:

(i) Δ APD Δ CQB
(ii) AP = CQ
(iii) Δ AQB Δ CPD
(iv) AQ = CP
(v) APCQ is a parallelogram

Question 10. ABCD is a parallelogram and AP and CQ are perpendiculars from vertices A and C on diagonal BD (see Fig. 8.21). Show that :

(i) Δ APB Δ CQD
(ii) AP = CQ

Question 11. In Δ ABC and Δ DEF, AB = DE, AB || DE, BC = EF and BC || EF. Vertices A, B and C are joined to vertices D, E and F respectively (see Fig. 8.22). Show that :

(i) quadrilateral ABED is a parallelogram
(ii) quadrilateral BEFC is a parallelogram
(iii) AD || CF and AD = CF
(iv) quadrilateral ACFD is a parallelogram
(v) AC = DF
(vi) Δ ABC Δ DEF.

Question 12. ABCD is a trapezium in which AB || CD and AD = BC (see Fig. 8.23). Show that:

(i) ∠ A = ∠ B
(ii) ∠ C = ∠ D
(iii) Δ ABC Δ BAD
(iv) diagonal AC = diagonal BD [Hint : Extend AB and draw a line through C parallel to DA intersecting AB produced at E.]

EXERCISE 8.2

Question 1. ABCD is a quadrilateral in which P, Q, R and S are mid-points of the sides AB, BC, CD and DA (see Fig 8.29). AC is a diagonal. Show that :

(i) SR || AC and SR = 1 2 AC
(ii) PQ = SR
(iii) PQRS is a parallelogram.

Question 2. ABCD is a rhombus and P, Q, R and S are ©wthe mid-points of the sides AB, BC, CD and DA respectively. Show that the quadrilateral PQRS is a rectangle.

Question 3. ABCD is a rectangle and P, Q, R and S are mid-points of the sides AB, BC, CD and DA respectively. Show that the quadrilateral PQRS is a rhombus.

Question 4. ABCD is a trapezium in which AB || DC, BD is a diagonal and E is the mid-point of AD. A line is drawn through E parallel to AB intersecting BC at F (see Fig. 8.30). Show that F is the mid-point of BC.

Question 5. In a parallelogram ABCD, E and F are the mid-points of sides AB and CD respectively (see Fig. 8.31). Show that the line segments AF and EC trisect the diagonal BD.

Question 6. Show that the line segments joining the mid-points of the opposite sides of a quadrilateral bisect each other.

Question 7. ABC is a triangle right angled at C. A line through the mid-point M of hypotenuse AB and parallel to BC intersects AC at D. Show that:

(i) D is the mid-point of AC
(ii) MD ⊥ AC
(iii) CM = MA = 1 2 AB


(Mathematics) Chapter 9 Areas of Parallelograms and Triangles


EXERCISE 9.1

Question1. Which of the following figures lie on the same base and between the same parallels. In such a case, write the common base and the two parallels. 

EXERCISE 9.2

Question 1. In Fig. 9.15, ABCD is a parallelogram, AE ⊥ DC and CF ⊥ AD. If AB = 16 cm, AE = 8 cm and CF = 10 cm, find AD.

Question 2. If E,F,G and H are respectively the mid-points of the sides of a parallelogram ABCD, show that ar (EFGH) = 1 ar (ABCD) 2 .

Question 3. P and Q are any two points lying on the sides DC and AD respectively of a parallelogram ABCD. Show that ar (APB) = ar (BQC).

Question 4. In Fig. 9.16, P is a point in the interior of a parallelogram ABCD. Show that:

(i) ar (APB) + ar (PCD) = 1 ar (ABCD) 2
(ii) ar (APD) + ar (PBC) = ar (APB) + ar (PCD) [Hint : Through P, draw a line parallel to AB.]

Question 5. . In Fig. 9.17, PQRS and ABRS are parallelograms and X is any point on side BR. Show that

(i) ar (PQRS) = ar (ABRS)
(ii) ar (AX S) = 1 ar (PQRS)

Question 6. A farmer was having a field in the form of a parallelogram PQRS. She took any point A on RS and joined it to points P and Q. In how many parts the fields is divided? What are the shapes of these parts? The farmer wants to sow wheat and pulses in equal portions of the field separately. How should she do it?

EXERCISE 9.3

Question 1. In Fig.9.23, E is any point on median AD of a Δ ABC. Show that ar (ABE) = ar (ACE).

Question 2. In a triangle ABC, E is the mid-point of median AD. Show that ar (BED) = 1 ar(ABC) 4 .

Question 2. Show that the diagonals of a parallelogram divide it into four triangles of equal area.

Question 4. In Fig. 9.24, ABC and ABD are two triangles on the same base AB. If line- segment CD is bisected by AB at O, show that ar(ABC) = ar (ABD).

Question 5. D, E and F are respectively the mid-points of the sides BC, CA and AB of a Δ ABC. Show that

(i) BDEF is a parallelogram.
(ii) ar (DEF) = 1 4 ar (ABC)
(iii) ar (BDEF) = 1 2 ar (ABC)

Question 6. In Fig. 9.25, diagonals AC and BD of quadrilateral ABCD intersect at O such that OB = OD. If AB = CD, then show that:

(i) ar (DOC) = ar (AOB)
(ii) ar (DCB) = ar (ACB)
(iii) DA || CB or ABCD is a parallelogram. [Hint : From D and B, draw perpendiculars to AC.]

Question 7. D and E are points on sides AB and AC respectively of Δ ABC such that ar (DBC) = ar (EBC). Prove that DE || BC.

Question 8. XY is a line parallel to side BC of a triangle ABC. If BE || AC and CF || AB meet XY at E and F respectively, show that ar (ABE) = ar (ACF)

Question 9. The side AB of a parallelogram ABCD is produced to any point P. A line through A and parallel to CP meets CB produced at Q and then parallelogram PBQR is completed (see Fig. 9.26). Show that ar (ABCD) = ar (PBQR). [Hint : Join AC and PQ. Now compare ar (ACQ) and ar (APQ).]

Question 10. Diagonals AC and BD of a trapezium ABCD with AB || DC intersect each other at O. Prove that ar (AOD) = ar (BOC).

Question 11. In Fig. 9.27, ABCDE is a pentagon. A line through B parallel to AC meets DC produced at F. Show that

(i) ar (ACB) = ar (ACF)
(ii) ar (AEDF) = ar (ABCDE)

Question 12. A villager Itwaari has a plot of land of the shape of a quadrilateral. The Gram Panchayat of the village decided to take over some portion of his plot from one of the corners to construct a Health Centre. Itwaari agrees to the above proposal with the condition that he should be given equal amount of land in lieu of his land adjoining his plot so as to form a triangular plot. Explain how this proposal will be implemented.

Question 13. ABCD is a trapezium with AB || DC. A line parallel to AC intersects AB at X and BC at Y. Prove that ar (ADX) = ar (ACY). [Hint : Join CX.]

Question 14. In Fig.9.28, AP || BQ || CR. Prove that ar (AQC) = ar (PBR).

Question 15. . Diagonals AC and BD of a quadrilateral ABCD intersect at O in such a way that ar (AOD) = ar (BOC). Prove that ABCD is a trapezium.

Question 16. In Fig.9.29, ar (DRC) = ar (DPC) and ar (BDP) = ar (ARC). Show that both the quadrilaterals ABCD and DCPR are trapeziums.

EXERCISE 9.4

Question 1. Parallelogram ABCD and rectangle ABEF are on the same base AB and have equal areas. Show that the perimeter of the parallelogram is greater than that of the rectangle.

Question 2. In Fig. 9.30, D and E are two points on BC such that BD = DE = EC. Show that ar (ABD) = ar (ADE) = ar (AEC). Can you now answer the question that you have left in the 'Introduction' of this chapter, whether the field of Budhia has been actually divided into three parts of equal area? triangles ABD, ADE and AEC of equal areas. In the same way, by dividing BC into n equal parts and joining the points of division so obtained to the opposite vertex of BC, you can divide ΔABC into n triangles of equal areas.]

Question 3. In Fig. 9.31, ABCD, DCFE and ABFE are parallelograms. Show that ar (ADE) = ar (BCF).

Question 4. In Fig. 9.32, ABCD is a parallelogram and BC is produced to a point Q such that AD = CQ. If AQ intersect DC at P, show that ar (BPC) = ar (DPQ). [Hint : Join AC.]

Question 5. In Fig.9.33, ABC and BDE are two equilateral triangles such that D is the mid-point of BC. If AE intersects BC at F, show that:

(i) ar (BDE) = 1 4 ar (ABC)
(ii) ar (BDE) = 1 2 ar (BAE)
(iii) ar (ABC) = 2 ar (BEC)
(iv) ar (BFE) = ar (AFD)
(v) ar (BFE) = 2 ar (FED)
(vi) ar (FED) = 1 8 ar (AFC) [Hint : Join EC and AD. Show that BE || AC and DE || AB, etc.]

Question 6. Diagonals AC and BD of a quadrilateral ABCD intersect each other at P. Show that ar (APB) × ar (CPD) = ar (APD) × ar (BPC). [Hint : From A and C, draw perpendiculars to BD.]

Question 7. P and Q are respectively the mid-points of sides AB and BC of a triangle ABC and R is the mid-point of AP, show that :

(i) ar (PRQ) = 1 2 ar (ARC)
(ii) ar (RQC) = 3 8 ar (ABC)
(iii) ar (PBQ) = ar (ARC)

Question 8. In Fig. 9.34, ABC is a right triangle right angled at A. BCED, ACFG and ABMN are squares on the sides BC, CA and AB respectively. Line segment AX ⊥ DE meets BC at Y. Show that:

(i) Δ MBC Δ ABD
(ii) ar (BYXD) = 2 ar (MBC)
(iii) ar (BYXD) = ar (ABMN)
(iv) Δ FCB Δ ACE
(v) ar (CYXE) = 2 ar (FCB)
(vi) ar (CYXE) = ar (ACFG)
(vii) ar (BCED) = ar (ABMN) + ar (ACFG) Note : Result
(vii) is the famous Theorem of Pythagoras. You shall learn a simpler proof of this theorem in Class X.


(Mathematics) Chapter 10 Circles


EXERCISE 10.1

Question 1. Fill in the blanks:

(i) The centre of a circle lies in of the circle. (exterior/ interior)
(ii) A point, whose distance from the centre of a circle is greater than its radius lies in of the circle. (exterior/ interior)
(iii) The longest chord of a circle is a of the circle.
(iv) An arc is a when its ends are the ends of a diameter.
(v) Segment of a circle is the region between an arc and of the circle.
(vi) A circle divides the plane, on which it lies, in parts.

Question 2. Write True or False: Give reasons for your answers.

(i) Line segment joining the centre to any point on the circle is a radius of the circle.
(ii) A circle has only finite number of equal chords.
(iii) If a circle is divided into three equal arcs, each is a major arc.
(iv) A chord of a circle, which is twice as long as its radius, is a diameter of the circle.
(v) Sector is the region between the chord and its corresponding arc.
(vi) A circle is a plane figure.

EXERCISE 10.2

Question 1. Recall that two circles are congruent if they have the same radii. Prove that equal chords of congruent circles subtend equal angles at their centres.

Question 2. Prove that if chords of congruent circles subtend equal angles at their centres, then the chords are equal.

EXERCISE 10.3

Question 1. Draw different pairs of circles. How many points does each pair have in common? What is the maximum number of common points?

Question 2. Suppose you are given a circle. Give a construction to find its centre.

Question 3. If two circles intersect at two points, prove that their centres lie on the perpendicular

EXERCISE 10.4

Question 1. Two circles of radii 5 cm and 3 cm intersect at two points and the distance between their centres is 4 cm. Find the length of the common chord.

Question 2. If two equal chords of a circle intersect within the circle, prove that the segments of one chord are equal to corresponding segments of the other chord.

Question 3. If two equal chords of a circle intersect within the circle, prove that the line joining the point of intersection to the centre makes equal angles with the chords.

Question 4.
If a line intersects two concentric circles (circles with the same centre) with centre O at A, B, C and D, prove that AB = CD (see Fig. 10.25).

Question 5. Three girls Reshma, Salma and Mandip are playing a game by standing on a circle of radius 5m drawn in a park. Reshma throws a ball to Salma, Salma to Mandip, Mandip to Reshma. If the distance between Reshma and Salma and between Salma and Mandip is 6m each, what is the distance between Reshma and Mandip?

Question 6. A circular park of radius 20m is situated in a colony. Three boys Ankur, Syed and David are sitting at equal distance on its boundary each having a toy telephone in his hands to talk each other. Find the length of the string of each phone.

EXERCISE 10.5

Question 1. In Fig. 10.36, A,B and C are three points on a circle with centre O such that ∠ BOC = 30° and ∠ AOB = 60°. If D is a point on the circle other than the arc ABC, find ∠ADC

Question 2. A chord of a circle is equal to the radius of the circle. Find the angle subtended by the chord at a point on the minor arc and also at a point on the major arc.

Question 3. In Fig. 10.37, ∠ PQR = 100°, where P, Q and R are points on a circle with centre O. Find ∠ OPR.

Question 4. In Fig. 10.38, ∠ ABC = 69°, ∠ ACB = 31°, find ∠ BDC.

Question 5. In Fig. 10.39, A, B, C and D are four points on a circle. AC and BD intersect at a point E such that ∠ BEC = 130° and ∠ ECD = 20°. Find ∠ BAC.

Question 6. ABCD is a cyclic quadrilateral whose diagonals intersect at a point E. If ∠ DBC = 70°, ∠ BAC is 30°, find ∠ BCD. Further, if AB = BC, find ∠ ECD.

Question 7. If diagonals of a cyclic quadrilateral are diameters of the circle through the vertices of the quadrilateral, prove that it is a rectangle.

Question 8. If the non-parallel sides of a trapezium are equal, prove that it is cyclic.

Question 9. Two circles intersect at two points B and C. Through B, two line segments ABD and PBQ are drawn to intersect the circles at A, D and P, Q respectively (see Fig. 10.40). Prove that ∠ ACP = ∠ QCD.

Question 10. If circles are drawn taking two sides of a triangle as diameters, prove that the point of intersection of these circles lie on the third side.

Question 11. ABC and ADC are two right triangles with common hypotenuse AC. Prove that ∠ CAD = ∠ CBD.

Question 12. Prove that a cyclic parallelogram is a rectangle.

EXERCISE 10.6

Question 1. Prove that the line of centres of two intersecting circles subtends equal angles at the two points of intersection.

Question 2. Two chords AB and CD of lengths 5 cm and 11 cm respectively of a circle are parallel to each other and are on opposite sides of its centre. If the distance between AB and CD is 6 cm, find the radius of the circle.

Question 3. The lengths of two parallel chords of a circle are 6 cm and 8 cm. If the smaller chord is at distance 4 cm from the centre, what is the distance of the other chord from the centre?

Question 4. Let the vertex of an angle ABC be located outside a circle and let the sides of the angle intersect equal chords AD and CE with the circle. Prove that ∠ABC is equal to half the difference of the angles subtended by the chords AC and DE at the centre.

Question 5. Prove that the circle drawn with any side of a rhombus as diameter, passes through the point of intersection of its diagonals.

Question 6. ABCD is a parallelogram. The circle through A, B and C intersect CD (produced if necessary) at E. Prove that AE = AD.

Question 7. AC and BD are chords of a circle which bisect each other. Prove that :

(i) AC and BD are diameters
(ii) ABCD is a rectangle.

Question 8. Bisectors of angles A, B and C of a triangle ABC intersect its circumcircle at D, E and F respectively. Prove that the angles of the triangle DEF are 90° – 1 2 A, 90° – 1 2 B and 90° – 1 2 C.


(Mathematics) Chapter 11 Constructions


EXERCISE 11.1

Question 1. Construct an angle of 900 at the initial point of a given ray and justify the construction.

Question 2. Construct an angle of 450 at the initial point of a given ray and justify the construction.

Question 3. Construct the angles of the following measurements:
(i) 30°
(ii) 22 1 2 °
(iii) 15°

Question 4. Construct the following angles and verify by measuring them by a protractor:
(i) 75°
(ii) 105°
(iii) 135°

Question 5. Construct an equilateral triangle, given its side and justify the construction. 

EXERCISE 11.2

Question 1. Construct a triangle ABC in which BC = 7cm, ∠B = 75° and AB + AC = 13 cm.

Question 2. Construct a triangle ABC in which BC = 8cm, ∠B = 45° and AB – AC = 3.5 cm.

Question 3. Construct a triangle PQR in which QR = 6cm, ∠Q = 60° and PR – PQ = 2cm.

Question 4. Construct a triangle XYZ in which ∠Y = 30°, ∠Z = 90° and XY + YZ + ZX = 11 cm.

Question 5. Construct a right triangle whose base is 12cm and sum of its hypotenuse and other side is 18 cm.


(Mathematics) Chapter 12 Heron's Formula



EXERCISE 12.1

Question 1. A traffic signal board, indicating 'SCHOOL AHEAD', is an equilateral triangle with side 'a'. Find the area of the signal board, using Heron's formula. If its perimeter is 180 cm, what will be the area of the signal board?

Question 2. The triangular side walls of a flyover have been used for advertisements. The sides of the walls are 122 m, 22 m and 120 m (see Fig. 12.9). The advertisements yield an earning of Rs 5000 per m2 per year. A company hired one of its walls for 3 months. How much rent did it pay? 

Question 3. There is a slide in a park. One of its side walls has been painted in some colour with a message "KEEP THE PARK GREEN AND CLEAN" (see Fig. 12.10 ). If the sides of the wall are 15 m, 11 m and 6 m, find the area painted in colour. Fig. 12.10

Question 4. Find the area of a triangle two sides of which are 18cm and 10cm and the perimeter is 42cm.

Question 5. Sides of a triangle are in the ratio of 12 : 17 : 25 and its perimeter is 540cm. Find its area. 6. An isosceles triangle has perimeter 30 cm and each of the equal sides is 12 cm. Find the area of the triangle.

EXERCISE 12.2

Question 1. A park, in the shape of a quadrilateral ABCD, has ∠ C = 90º, AB = 9 m, BC = 12 m, CD = 5 m and AD = 8 m. How much area does it occupy?

Question 2. Find the area of a quadrilateral ABCD in which AB = 3 cm, BC = 4 cm, CD = 4 cm, DA = 5 cm and AC = 5 cm.

Question 3. Radha made a picture of an aeroplane with coloured paper as shown in Fig 12.15. Find the total area of the paper used.

Question 4. A triangle and a parallelogram have the same base and the same area. If the sides of the triangle are 26 cm, 28 cm and 30 cm, and the parallelogram stands on the base 28 cm, find the height of the parallelogram. Fig. 12.14

Question 5. A rhombus shaped field has green grass for 18 cows to graze. If each side of the rhombus is 30 m and its longer diagonal is 48 m, how much area of grass field will each cow be getting?

Question 6. An umbrella is made by stitching 10 triangular pieces of cloth of two different colours (see Fig. 12.16), each piece measuring 20 cm, 50 cm and 50 cm. How much cloth of each colour is required for the umbrella? 7. A kite in the shape of a square with a diagonal 32 cm and an isosceles triangle of base 8 cm and sides 6 cm each is to be made of three different shades as shown in Fig. 12.1

Question 7. How much paper of each shade has been used in it?

Question 8. A floral design on a floor is made up of 16 tiles which are triangular, the sides of the triangle being 9 cm, 28 cm and 35 cm (see Fig. 12.18). Find the cost of polishing the tiles at the rate of 50p per cm2.

Question 9. A field is in the shape of a trapezium whose parallel sides are 25 m and 10 m. The non-parallel sides are 14 m and 13 m. Find the area of the field. 


(Mathematics) Chapter 13 Surface Areas and Volumes


EXERCISE 13.1

Question 1. A plastic box 1.5 m long, 1.25 m wide and 65 cm deep is to be made. It is to be open at the top. Ignoring the thickness of the plastic sheet, determine:

(i) The area of the sheet required for making the box.
(ii) The cost of sheet for it, if a sheet measuring 1m2 costs Rs 20.

Question 2. The length, breadth and height of a room are 5 m, 4 m and 3 m respectively. Find the cost of white washing the walls of the room and the ceiling at the rate of Rs 7.50 per m2.

Question 3. The floor of a rectangular hall has a perimeter 250 m. If the cost of painting the four walls at the rate of Rs 10 per m2 is Rs 15000, find the height of the hall. [Hint : Area of the four walls = Lateral surface area.]

Question 4. The paint in a certain container is sufficient to paint an area equal to 9.375 m2. How many bricks of dimensions 22.5 cm × 10 cm × 7.5 cm can be painted out of this container?

Question 5. A cubical box has each edge 10 cm and another cuboidal box is 12.5 cm long, 10 cm wide and 8 cm high.

(i) Which box has the greater lateral surface area and by how much?
(ii) Which box has the smaller total surface area and by how much?

Question 6. A small indoor greenhouse (herbarium) is made entirely of glass panes (including base) held together with tape. It is 30 cm long, 25 cm wide and 25 cm high.

(i) What is the area of the glass?
(ii) How much of tape is needed for all the 12 edges?

Question 7. Shanti Sweets Stall was placing an order for making cardboard boxes for packing their sweets. Two sizes of boxes were required. The bigger of dimensions 25 cm × 20 cm × 5 cm and the smaller of dimensions 15 cm × 12 cm × 5 cm. For all the overlaps, 5% of the total surface area is required extra. If the cost of the cardboard is Rs 4 for 1000 cm2, find the cost of cardboard required for supplying 250 boxes of each kind.

Question 8. Parveen wanted to make a temporary shelter for her car, by making a box-like structure with tarpaulin that covers all the four sides and the top of the car (with the front face as a flap which can be rolled up). Assuming that the stitching margins are very small, and therefore negligible, how much tarpaulin would be required to make the shelter of height 2.5 m, with base dimensions 4 m × 3 m?

EXERCISE 13.2

Assume π = 22/7 , unless stated otherwise.

Question 1. The curved surface area of a right circular cylinder of height 14 cm is 88 cm2. Find the diameter of the base of the cylinder.

Question 2. It is required to make a closed cylindrical tank of height 1 m and base diameter 140 cm from a metal sheet. How many square metres of the sheet are required for the same?

Question 3. A metal pipe is 77 cm long. The inner diameter of a cross section is 4 cm, the outer diameter being 4.4 cm (see Fig. 13.11). Find its

(i) inner curved surface area,
(ii) outer curved surface area,
(iii) total surface area.

Question 4. The diameter of a roller is 84 cm and its length is 120 cm. It takes 500 complete revolutions to move once over to level a playground. Find the area of the playground in m2.

Question 5. A cylindrical pillar is 50 cm in diameter and 3.5 m in height. Find the cost of painting the curved surface of the pillar at the rate of Rs 12.50 per m2.

Question 6. Curved surface area of a right circular cylinder is 4.4 m2. If the radius of the base of the cylinder is 0.7 m, find its height.

Question 7. The inner diameter of a circular well is 3.5 m. It is 10 m deep. Find

(i) its inner curved surface area,
(ii) the cost of plastering this curved surface at the rate of Rs 40 per m2.

Question 8. In a hot water heating system, there is a cylindrical pipe of length 28 m and diameter 5 cm. Find the total radiating surface in the system.

Question 9. Find

(i) the lateral or curved surface area of a closed cylindrical petrol storage tank that is 4.2 m in diameter and 4.5 m high.
(ii) how much steel was actually used, if 1 12 of the steel actually used was wasted in making the tank.

Question 10. In Fig. 13.12, you see the frame of a lampshade. It is to be covered with a decorative cloth. The frame has a base diameter of 20 cm and height of 30 cm. A margin of 2.5 cm is to be given for folding it over the top and bottom of the frame. Find how much cloth is required for covering the lampshade.

Question 11. The students of a Vidyalaya were asked to participate in a competition for making and decorating penholders in the shape of a cylinder with a base, using cardboard. Each penholder was to be of radius 3 cm and height 10.5 cm. The Vidyalaya was to supply the competitors with cardboard. If there were 35 competitors, how much cardboard was required to be bought for the competition?

EXERCISE 13.3

Assume π = 22/7 , unless stated otherwise.

Question 1. Diameter of the base of a cone is 10.5 cm and its slant height is 10 cm. Find its curved surface area.

Question 2. Find the total surface area of a cone, if its slant height is 21 m and diameter of its base is 24 m. 3. Curved surface area of a cone is 308 cm2 and its slant height is 14 cm. Find

(i) radius of the base and
(ii) total surface area of the cone.

Question 4. A conical tent is 10 m high and the radius of its base is 24 m. Find

(i) slant height of the tent.
(ii) cost of the canvas required to make the tent, if the cost of 1 m2 canvas is Rs 70.

Question 5. What length of tarpaulin 3 m wide will be required to make conical tent of height 8 m and base radius 6 m? Assume that the extra length of material that will be required for stitching margins and wastage in cutting is approximately 20 cm (Use π = 3.14).

Question 6. The slant height and base diameter of a conical tomb are 25 m and 14 m respectively. Find the cost of white-washing its curved surface at the rate of Rs 210 per 100 m2.

Question 7. A joker's cap is in the form of a right circular cone of base radius 7 cm and height 24 cm. Find the area of the sheet required to make 10 such caps.

Question 8. A bus stop is barricaded from the remaining part of the road, by using 50 hollow cones made of recycled cardboard. Each cone has a base diameter of 40 cm and height 1 m. If the outer side of each of the cones is to be painted and the cost of painting is Rs 12 per m2, what will be the cost of painting all these cones? (Use π = 3.14 and take 1.04 = 1.02)

EXERCISE 13.4

Assume π = 22/7 , unless stated otherwise.

Question 1. Find the surface area of a sphere of radius:

(i) 10.5 cm
(ii) 5.6 cm
(iii) 14 cm

Question 2. Find the surface area of a sphere of diameter:

(i) 14 cm
(ii) 21 cm
(iii) 3.5 m

Question 3. Find the total surface area of a hemisphere of radius 10 cm. (Use π = 3.14)

Question 4. The radius of a spherical balloon increases from 7 cm to 14 cm as air is being pumped into it. Find the ratio of surface areas of the balloon in the two cases.

Question 5. A hemispherical bowl made of brass has inner diameter 10. 5 cm. Find the cost of tin-plating it on the inside at the rate of Rs 16 per 100 cm2.

Question 6. Find the radius of a sphere whose surface area is 154 cm2.

Question 7. The diameter of the moon is approximately one fourth of the diameter of the earth. Find the ratio of their surface areas.

Question 8. A hemispherical bowl is made of steel, 0.25 cm thick. The inner radius of the bowl is 5 cm. Find the outer curved surface area of the bowl.

Question 9. A right circular cylinder just encloses a sphere of radius r (see Fig. 13.22).Find

(i) surface area of the sphere,
(ii) curved surface area of the cylinder,
(iii) ratio of the areas obtained in
(i) and (ii). cm × 2.5 cm × 1.5 cm. What will be the volume of a packet containing 12 such boxes?

EXERCISE 13.5

Question 1. A matchbox measures 4 cm × 2.5 cm × 1.5 cm. What will be the volume of a packet containing 12 such boxes?

Question 2. A cuboidal water tank is 6 m long, 5 m wide and 4.5 m deep. How many litres of water can it hold? (1 m3 = 1000 l)

Question 3. A cuboidal vessel is 10 m long and 8 m wide. How high must it be made to hold 380 cubic metres of a liquid?

Question 4. Find the cost of digging a cuboidal pit 8 m long, 6 m broad and 3 m deep at the rate of Rs 30 per m3.

Question 5. The capacity of a cuboidal tank is 50000 litres of water. Find the breadth of the tank, if its length and depth are respectively 2.5 m and 10 m.

Question 6. A village, having a population of 4000, requires 150 litres of water per head per day. It has a tank measuring 20 m × 15 m × 6 m. For how many days will the water of this tank last?

Question 7. A godown measures 40 m × 25 m × 10 m. Find the maximum number of wooden crates each measuring 1.5 m × 1.25 m × 0.5 m that can be stored in the godown.

Question 8. A solid cube of side 12 cm is cut into eight cubes of equal volume. What will be the side of the new cube? Also, find the ratio between their surface areas. 9. A river 3 m deep and 40 m wide is flowing at the rate of 2 km per hour. How much water will fall into the sea in a minute?

EXERCISE 13.6

Assume π = 22/7 , unless stated otherwise.

Question 1. The circumference of the base of a cylindrical vessel is 132 cm and its height is 25 cm. How many litres of water can it hold? (1000 cm3 = 1l)

Question 2. The inner diameter of a cylindrical wooden pipe is 24 cm and its outer diameter is 28 cm. The length of the pipe is 35 cm. Find the mass of the pipe, if 1 cm3 of wood has a mass of 0.6 g.

Question 3. A soft drink is available in two packs - (i) a tin can with a rectangular base of length5 cm and width 4 cm, having a height of 15 cm and (ii) a plastic cylinder with circular base of diameter 7 cm and height 10 cm. Which container has greater capacity and by how much?

Question 4. If the lateral surface of a cylinder is 94.2 cm2 and its height is 5 cm, then find (i) radius of its base (ii) its volume. (Use π = 3.14)

Question 5. It costs Rs 2200 to paint the inner curved surface of a cylindrical vessel 10 m deep. If the cost of painting is at the rate of Rs 20 per m2, find

(i) inner curved surface area of the vessel,
(ii) radius of the base,
(iii) capacity of the vessel.

Question 6. The capacity of a closed cylindrical vessel of height 1 m is 15.4 litres. How many square metres of metal sheet would be needed to make it?

Question 7. A lead pencil consists of a cylinder of wood with a solid cylinder of graphite filled in the interior. The diameter of the pencil is 7 mm and the diameter of the graphite is 1 mm. If the length of the pencil is 14 cm, find the volume of the wood and that of the graphite.

Question 8. A patient in a hospital is given soup daily in a cylindrical bowl of diameter 7 cm. If the bowl is filled with soup to a height of 4 cm, how much soup the hospital has to prepare daily to serve 250 patients

EXERCISE 13.7

Assume π = 22/7 , unless stated otherwise.

Question 1. Find the volume of the right circular cone with (i) radius 6 cm, height 7 cm (ii) radius 3.5 cm, height 12 cm

Question 2. Find the capacity in litres of a conical vessel with (i) radius 7 cm, slant height 25 cm (ii) height 12 cm, slant height 13 cm

Question 3. The height of a cone is 15 cm. If its volume is 1570 cm3, find the radius of the base. (Use π = 3.14)

Question 4. If the volume of a right circular cone of height 9 cm is 48 π cm3, find the diameter of its base.

Question 5. A conical pit of top diameter 3.5 m is 12 m deep. What is its capacity in kilolitres?

Question 6. The volume of a right circular cone is 9856 cm3. If the diameter of the base is 28 cm, find

(i) height of the cone
(ii) slant height of the cone
(iii) curved surface area of the cone

Question7. A right triangle ABC with sides 5 cm, 12 cm and 13 cm is revolved about the side 12 cm. Find the volume of the solid so obtained.

Question 8. If the triangle ABC in the Question 7 above is revolved about the side 5 cm, then find the volume of the solid so obtained. Find also the ratio of the volumes of the two solids obtained in Questions 7 and 8.

Question 9. A heap of wheat is in the form of a cone whose diameter is 10.5 m and height is 3 m. Find its volume. The heap is to be covered by canvas to protect it from rain. Find the area of the canvas required.

EXERCISE 13.8

Assume π = 22/7 , unless stated otherwise.

Question 1. Find the volume of a sphere whose radius is (i) 7 cm (ii) 0.63 m

Question 2. Find the amount of water displaced by a solid spherical ball of diameter (i) 28 cm (ii) 0.21 m

Question 3. The diameter of a metallic ball is 4.2 cm. What is the mass of the ball, if the density of the metal is 8.9 g per cm3?

Question 4. The diameter of the moon is approximately one-fourth of the diameter of the earth. What fraction of the volume of the earth is the volume of the moon?

Question 5. How many litres of milk can a hemispherical bowl of diameter 10.5 cm hold?

Question 6. A hemispherical tank is made up of an iron sheet 1 cm thick. If the inner radius is 1 m, then find the volume of the iron used to make the tank.

Question 7. Find the volume of a sphere whose surface area is 154 cm2.

Question 8. A dome of a building is in the form of a hemisphere. From inside, it was white-washed at the cost of Rs 498.96. If the cost of white-washing is Rs 2.00 per square metre, find the
(i) inside surface area of the dome,
(ii) volume of the air inside the dome.

Question 9. Twenty seven solid iron spheres, each of radius r and surface area S are melted to form a sphere with surface area S. Find the (i) radius r of the new sphere, (ii) ratio of S and S′.

Question 10. A capsule of medicine is in the shape of a sphere of diameter 3.5 mm. How much medicine (in mm3) is needed to fill this capsule?

EXERCISE 13.9

Question 1. A wooden bookshelf has external dimensions as follows: Height = 110 cm, Depth = 25 cm, Breadth = 85 cm (see Fig. 13.31). The thickness of the plank is 5 cm everywhere. The external faces are to be polished and the inner faces are to be painted. If the rate of polishing is 20 paise per cm2 and the rate of painting is 10 paise per cm2, find the total expenses required for polishing and painting the surface of the bookshelf.

Question 2. The front compound wall of a house is decorated by wooden spheres of diameter 21 cm, placed on small supports as shown in Fig 13.32. Eight such spheres are used for this purpose, and are to be painted silver. Each support is a cylinder of radius 1.5 cm and height 7 cm and is to be painted black. Find the cost of paint required if silver paint costs 25 paise per cm2 and black paint costs 5 paise per cm2.

Question 3. The diameter of a sphere is decreased by 25%. By what per cent does its curved surface area decrease?


(Mathematics) Chapter 14 Statistics


EXERCISE 14.1

Question 1. Give five examples of data that you can collect from your day-to-day life. 2. Classify the data in Q.1 above as primary or secondary data.

EXERCISE 14.2

Question 1. The blood groups of 30 students of Class VIII are recorded as follows:

A, B, O, O, AB, O, A, O, B, A, O, B, A, O, O,
A, AB, O, A, A, O, O, AB, B, A, O, B, A, B, O.
Represent this data in the form of a frequency distribution table. Which is the most common, and which is the rarest, blood group among these students?

Question 2. The distance (in km) of 40 engineers from their residence to their place of work were found as follows:

5 3 10 20 25 11 13 7 12 31
19 10 12 17 18 11 32 17 16 2
7 9 7 8 3 5 12 15 18 3
12 14 2 9 6 15 15 7 6 12

Construct a grouped frequency distribution table with class size 5 for the data given above taking the first interval as 05 (5 not included). What main features do you observe from this tabular representation?

Question 3. The relative humidity (in %) of a certain city for a month of 30 days was as follows:

98.1 98.6 99.2 90.3 86.5 95.3 92.9 96.3 94.2 95.1

89.2 92.3 97.1 93.5 92.7 95.1 97.2 93.3 95.2 97.3

96.2 92.1 84.9 90.2 95.7 98.3 97.3 96.1 92.1 89

(i) Construct a grouped frequency distribution table with classes 84 - 86, 86 - 88, etc.
(ii) Which month or season do you think this data is about?
(iii) What is the range of this data?

Question 4. The heights of 50 students, measured to the nearest centimetres, have been found to be as follows:

161 150 154 165 168 161 154 162 150 151
162 164 171 165 158 154 156 172 160 170
153 159 161 170 162 165 166 168 165 164
154 152 153 156 158 162 160 161 173 166
161 159 162 167 168 159 158 153 154 159

(i) Represent the data given above by a grouped frequency distribution table, taking the class intervals as 160 - 165, 165 - 170, etc.
(ii) What can you conclude about their heights from the table?

Question 5. A study was conducted to find out the concentration of sulphur dioxide in the air in parts per million (ppm) of a certain city. The data obtained for 30 days is as follows:

0.03 0.08 0.08 0.09 0.04 0.17
0.16 0.05 0.02 0.06 0.18 0.20
0.11 0.08 0.12 0.13 0.22 0.07
0.08 0.01 0.10 0.06 0.09 0.18
0.11 0.07 0.05 0.07 0.01 0.04

(i) Make a grouped frequency distribution table for this data with class intervals as 0.00 - 0.04, 0.04 - 0.08, and so on.
(ii) For how many days, was the concentration of sulphur dioxide more than 0.11 parts per million?

Question 6. Three coins were tossed 30 times simultaneously. Each time the number of heads occurring was noted down as follows:

0 1 2 2 1 2 3 1 3 0
1 3 1 1 2 2 0 1 2 1
3 0 0 1 1 2 3 2 2 0

Prepare a frequency distribution table for the data given above.

Question 7. The value of π upto 50 decimal places is given below:

3.14159265358979323846264338327950288419716939937510

(i) Make a frequency distribution of the digits from 0 to 9 after the decimal point.
(ii) What are the most and the least frequently occurring digits?

Question 8. Thirty children were asked about the number of hours they watched TV programmes in the previous week. The results were found as follows:

1 6 2 3 5 12 5 8 4 8
10 3 4 12 2 8 15 1 17 6
3 2 8 5 9 6 8 7 14 12

(i) Make a grouped frequency distribution table for this data, taking class width 5 and one of the class intervals as 5 - 10.
(ii) How many children watched television for 15 or more hours a week?

Question 9. A company manufactures car batteries of a particular type. The lives (in years) of 40 such batteries were recorded as follows:

2.6 3.0 3.7 3.2 2.2 4.1 3.5 4.5
3.5 2.3 3.2 3.4 3.8 3.2 4.6 3.7
2.5 4.4 3.4 3.3 2.9 3.0 4.3 2.8
3.5 3.2 3.9 3.2 3.2 3.1 3.7 3.4
4.6 3.8 3.2 2.6 3.5 4.2 2.9 3.6

Construct a grouped frequency distribution table for this data, using class intervals of size 0.5 starting from the interval 2 - 2.5.

EXERCISE 14.3

Question 1. A survey conducted by an organisation for the cause of illness and death among the women between the ages 15 - 44 (in years) worldwide, found the following figures (in %):

(i) Represent the information given above graphically.
(ii) Which condition is the major cause of women's ill health and death worldwide?
(iii) Try to find out, with the help of your teacher, any two factors which play a major role in the cause in (ii) above being the major cause.

Question 2. The following data on the number of girls (to the nearest ten) per thousand boys in different sections of Indian society is given below

(i) Represent the information above by a bar graph.
(ii) In the classroom discuss what conclusions can be arrived at from the graph.

Question 3. Given below are the seats won by different political parties in the polling outcome of a state assembly elections:

(i) Draw a bar graph to represent the polling results.
(ii) Which political party won the maximum number of seats?

Question 4. The length of 40 leaves of a plant are measured correct to one millimetre, and the obtained data is represented in the following table:

(i) Draw a histogram to represent the given data.
(ii) Is there any other suitable graphical representation for the same data?
(iii) Is it correct to conclude that the maximum number of leaves are 153 mm long? Why?

Question 5. The following table gives the life times of 400 neon lamps:

(i) Represent the given information with the help of a histogram.
(ii) How many lamps have a life time of more than 700 hours?

Question 6. The following table gives the distribution of students of two sections according to the marks obtained by them: Represent the marks of the students of both the sections on the same graph by two frequency polygons. From the two polygons compare the performance of the two sections.

Question 7. The runs scored by two teams A and B on the first 60 balls in a cricket match are given below: Represent the data of both the teams on the same graph by frequency polygons. [Hint : First make the class intervals continuous.]
Draw a histogram to represent the data above.

Question 8. 100 surnames were randomly picked up from a local telephone directory and a frequency distribution of the number of letters in the English alphabet in the surnames was found as follows:

(i) Draw a histogram to depict the given information.
(ii) Write the class interval in which the maximum number of surnames lie.

EXERCISE 14.4

Question 1. The following number of goals were scored by a team in a series of 10 matches:

2, 3, 4, 5, 0, 1, 3, 3, 4, 3 Find the mean, median and mode of these scores.

Question 2. In a mathematics test given to 15 students, the following marks (out of 100) are recorded:

41, 39, 48, 52, 46, 62, 54, 40, 96, 52, 98, 40, 42, 52, 60 Find the mean, median and mode of this data.

Question 3. The following observations have been arranged in ascending order. If the median of the data is 63, find the value of x.

29, 32, 48, 50, x, x + 2, 72, 78, 84, 95

Question 4. Find the mode of 14, 25, 14, 28, 18, 17, 18, 14, 23, 22, 14, 18.

Question 5. Find the mean salary of 60 workers of a factory from the following table:

Question 6. Give one example of a situation in which (i) the mean is an appropriate measure of central tendency. (ii) the mean is not an appropriate measure of central tendency but the median is an appropriate measure of central tendency.


(Mathematics) Chapter 15 Probability


EXERCISE 15.1

Question 1. In a cricket match, a batswoman hits a boundary 6 times out of 30 balls she plays. Find the probability that she did not hit a boundary.

Question 2. 1500 families with 2 children were selected randomly, and the following data were recorded:Compute the probability of a family, chosen at random, having
(i) 2 girls
(ii) 1 girl
(iii) No girl Also check whether the sum of these probabilities is 1.

Question 3. Refer to Example 5, Section 14.4, Chapter 14. Find the probability that a student of the class was born in August.

Question 4. Three coins are tossed simultaneously 200 times with the following frequencies of different outcomes: If the three coins are simultaneously tossed again, compute the probability of 2 heads coming up.

Question 5. An organisation selected 2400 families at random and surveyed them to determine a relationship between income level and the number of vehicles in a family. The information gathered is listed in the table below: Suppose a family is chosen. Find the probability that the family chosen is

(i) earning Rs 10000 – 13000 per month and owning exactly 2 vehicles.
(ii) earning Rs 16000 or more per month and owning exactly 1 vehicle.
(iii) earning less than Rs 7000 per month and does not own any vehicle.
(iv) earning Rs 13000 – 16000 per month and owning more than 2 vehicles.
(v) owning not more than 1 vehicle.

Question 6. Refer to Table 14.7, Chapter 14.

(i) Find the probability that a student obtained less than 20% in the mathematics test.
(ii) Find the probability that a student obtained marks 60 or above.

Question 7. To know the opinion of the students about the subject statistics, a survey of 200 students was conducted. The data is recorded in the following table Find the probability that a student chosen at random
(i) likes statistics, (ii) does not like it.

Question 8. Refer to Q.2, Exercise 14.2. What is the empirical probability that an engineer lives:

(i) less than 7 km from her place of work?
(ii) more than or equal to 7 km from her place of work?
(iii) within 1 2 km from her place of work?

Question 9. Activity : Note the frequency of two-wheelers, three-wheelers and four-wheelers going past during a time interval, in front of your school gate. Find the probability that any one vehicle out of the total vehicles you have observed is a two-wheeler.

Question 10. Activity : Ask all the students in your class to write a 3-digit number. Choose any student from the room at random. What is the probability that the number written by her/him is divisible by 3? Remember that a number is divisible by 3, if the sum of its digits is divisible by 3.

Question 11. Eleven bags of wheat flour, each marked 5 kg, actually contained the following weights of flour (in kg):
4.97 5.05 5.08 5.03 5.00 5.06 5.08 4.98 5.04 5.07 5.00
Find the probability that any of these bags chosen at random contains more than 5 kg of flour.

Question 12. In Q.5, Exercise 14.2, you were asked to prepare a frequency distribution table, regarding the concentration of sulphur dioxide in the air in parts per million of a certain city for 30 days. Using this table, find the probability of the concentration of sulphur dioxide in the interval 0.12 - 0.16 on any of these days.

Question 13. In Q.1, Exercise 14.2, you were asked to prepare a frequency distribution table regarding the blood groups of 30 students of a class. Use this table to determine the probability that a student of this class, selected at random, has blood group AB.


 

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NCERT Science Question Paper (Class-9)

Posted: 29 May 2018 12:14 AM PDT

NCERT  Science Question Paper (Class-9)


Chapter 1 Matter In Our Surroundings


Question 1. Which of the following are matter? Chair, air, love, smell, hate, almonds, thought, cold, colddrink, smell of perfume.

Question 2. Give reasons for the following observation: The smell of hot sizzling food reaches you several metres away, but to get the smell from cold food you have to go close.

Question 3. A diver is able to cut through water in a swimming pool. Which property of matter does this observation show?

Question 4. What are the characteristics of the particles of matter?

Question 5. The mass per unit volume of a substance is called density. (density = mass/volume). Arrange the following in order of increasing density – air, exhaust from chimneys, honey, water, chalk, cotton and iron.

Question 6. (a) Tabulate the differences in the characterisitcs of states of matter. (b) Comment upon the following: rigidity, compressibility, fluidity, filling a gas container, shape, kinetic energy and density.

Question 7. Give reasons
(a) A gas fills completely the vessel in which it is kept.
(b) A gas exerts pressure on the walls of the container. (c) A wooden table should be called a solid. (d) We can easily move our hand in air but to do the same through a solid block of wood we need a karate expert.

Question 8. Liquids generally have lower density as compared to solids. But you must have observed that ice floats on water. Find out why.

Question 9. Convert the following temperature to celsius scale: a. 300 K b. 573 K.

Question 10. What is the physical state of water at: a. 250ºC b. 100ºC ? 3. For any substance, why does the temperature remain constant during the change of state? 4. Suggest a method to liquefy atmospheric gases.

Question 11. Why does a desert cooler cool better on a hot dry day?

Question 12. How does the water kept in an earthen pot (matka) become cool during summer?

Question 13. Why does our palm feel cold when we put some acetone or petrol or perfume on it? 4. Why are we able to sip hot tea or milk faster from a saucer rather than a cup?

Question 14. What type of clothes should we wear in summer?

Question 15 1. Convert the following temperatures to the Celsius scale.

(a) 300 K
(b) 573 K.
 
Question 16. Convert the following temperatures to the Kelvin scale.

(a) 25°C
(b) 373°C.

Question 17. Give reason for the following observations.

(a) Naphthalene balls disappear with time without leaving any solid.
(b) We can get the smell of perfume sitting several metres away.

Question 18. Arrange the following substances in increasing order of forces of attraction between the particles— water, sugar, oxygen.

Question 19. What is the physical state of water at—

(a) 25°C
(b) 0°C
(c) 100°C ?

Question 20. Give two reasons to justify—

(a) water at room temperature is a liquid.
(b) an iron almirah is a solid at room temperature.

Question 21. Why is ice at 273 K more effective in cooling than water at the same temperature?

Question 22. What produces more severe burns, boiling water or steam?

Question 23. Name A,B,C,D,E and F in the following diagram showing change in its state


Chapter 2 Is Matter Around Us Pure


Question 1. What is meant by a pure substance?

Question 2. List the points of differences between homogeneous and heterogeneous mixtures.

Question 3. Differentiate between homogeneous and heterogeneous mixtures with examples.

Question 4. How are sol solution and suspension different from each other?

Question 5. To make a saturated solution 36 g of sodium chloride is dissolved in 100 g of water at 293 K. Find its concentration at this temperature.

Question 6. How will you separate a mixture containing kerosene and petrol (difference in their boiling points is more than 25ºC) which are miscible with each other?

Question 7. Name the technique to separate

(i) butter from curd
(ii) salt from sea-water
(iii) camphor from salt.

Question 8. What type of mixtures are separated by the technique of crystallisation?

Question 9. Classify the following as chemical or physical changes:

  • cutting of trees

  • melting of butter in a pan

  • rusting of almirah

  • boiling of water to form steam

  • passing of electric current through water and the water breaking down into hydrogen and oxygen gases

  • dissolving common salt in water

  • making a fruit salad with raw fruits and

  • burning of paper and wood.

Question 10. Try segregating the things around you as pure substances or mixtures. NCERT Solutions Intext Questions Page no.

Question 11. Which separation techniques will you apply for the separation of the following?

(a) Sodium chloride from its solution in water.
(b) Ammonium chloride from a mixture containing sodium chloride and ammonium chloride.
(c) Small pieces of metal in the engine oil of a car.
(d) Different pigments from an extract of flower petals.
(e) Butter from curd.
(f) Oil from water.
(g) Tea leaves from tea.
(h) Iron pins from sand.
(i) Wheat grains from husk.
(j) Fine mud particles suspended in water.

Question 12. Write the steps you would use for making tea. Use the words solution, solvent, solute, dissolve, soluble, insoluble, filtrate and residue.

Question 13. Pragya tested the solubility of three different substances at different temperatures and collected the data as given below (results are given in the following table, as grams of substance dissolved in 100 grams of water to form a saturated solution) .

(a) What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 K?
(b) Pragya makes a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature. What would she observe as the solution cools? Explain.
(c) Find the solubility of each salt at 293 K. Which salt has the highest solubility at this temperature?
(d) What is the effect of change of temperature on the solubility of a salt?

Question 14. Explain the following giving examples.

(a) saturated solution
(b) pure substance
(c) colloid
(d) suspension

Question 15. Classify each of the following as a homogeneous or heterogeneous mixture. soda water, wood, air, soil, vinegar, filtered tea.

Question 16. How would you confirm that a colourless liquid given to you is pure water?

Question 17. Which of the following materials fall in the category of a “pure substance”?

(a) Ice
(b) Milk
(c) Iron
(d) Hydrochloric acid
(e) Calcium oxide
(f) Mercury
(g) Brick
(h) Wood
(i) Air.

Question 18. Identify the solutions among the following mixtures.

(a) Soil
(b) Sea water
(c) Air
(d) Coal
(e) Soda water.

Question 19. Which of the following will show “Tyndall effect”?

(a) Salt solution
(b) Milk
(c) Copper sulphate solution
(d) Starch solution.

Question 20. Classify the following into elements, compounds and mixtures.

(a) Sodium
(b) Soil
(c) Sugar solution
(d) Silver
(e) Calcium carbonate
(f) Tin
(g) Silicon
(h) Coal
(i) Air
(j) Soap
(k) Methane
(l) Carbon dioxide
(m) Blood

Question 21. Which of the following are chemical changes?

(a) Growth of a plant
(b) Rusting of iron
(c) Mixing of iron filings and sand
(d) Cooking of food
(e) Digestion of food
(f) Freezing of water
(g) Burning of a candle.


Chapter 3 Atoms and Molecules


Quetion 1. In a reaction, 5.3 g of sodium carbonate reacted with 6 g of ethanoic acid. The products were 2.2 g of carbon = dioxide, 0.9 g water and 8.2 g of sodium ethanoate. Show that theseobservations are in agreement with the law of conservation of mass. sodium carbonate + ethanoic acid → sodium ethanoate + carbon dioxide + water

Quetion 2. Hydrogen and oxygen combine in the ratio of 1:8 by mass to form water. What mass of oxygen gas would be required to react completely with 3 g of hydrogen gas?

Quetion 3. Which postulate of Dalton’s atomic theory is the result of the law of conservation of mass?

Quetion 4. Which postulate of Dalton’s atomic theory can explain the law of definite proportions?

Quetion 5. Define the atomic mass unit.

Quetion 6. Why is it not possible to see an atom with naked eyes?

Quetion 7.Following formulae:

(i) Al2(SO4)3
(ii) CaCl2
(iii) K2SO4
(iv) KNO3
(v) CaCO3.

Question 8. What is meant by the term chemical formula?

Question 9. How many atoms are present in a

(i) H2S molecule and
(ii) PO4 3– ion?

Question 10. Write down the formulae of

(i) sodium oxide
(ii) aluminium chloride
(iii) sodium suphide
(iv) magnesium hydroxide

Question 11. Write down the names of compounds represented by the

Question 12. Calculate the molecular masses of H2, O2, Cl2, CO2, CH4, C2H6, C2H4, NH3, CH3OH.

Question 13. Calculate the formula unit masses of ZnO, Na2O, K2CO3, given atomic masses of Zn = 65 u, Na = 23 u, K = 39 u, C = 12 u, and O = 16 u.

Question 14. If one mole of carbon atoms weighs 12 gram, what is the mass (in gram) of 1 atom of carbon?

Question 15. Which has more number of atoms, 100 grams of sodium or 100 grams of iron (given, atomic mass of Na = 23 u, Fe = 56 u)?

Question 16. A 0.24 g sample of compound of oxygen and boron was found by analysis to contain 0.096 g of boron and 0.144 g of oxygen. Calculate the percentage composition of the compound by weight.

Question 17 . When 3.0 g of carbon is burnt in 8.00 g oxygen, 11.00 g of carbon dioxide is produced. What mass of carbon dioxide will be formed when 3.00 g of carbon is burnt in 50.00 g of oxygen? Which law of chemical combination will govern your answer?

Question 18. What are polyatomic ions? Give examples.

Question 19 Write the chemical formulae of the following.

(a) Magnesium chloride
(b) Calcium oxide
(c) Copper nitrate
(d) Aluminium chloride
(e) Calcium carbonate.

Question 20. Give the names of the elements present in the following compounds.

(a) Quick lime
(b) Hydrogen bromide
(c) Baking powder
(d) Potassium sulphate.

Question 21. Calculate the molar mass of the following substances.

(a) Ethyne, C2H2
(b) Sulphur molecule, S8
(c) Phosphorus molecule, P4 (Atomic mass of phosphorus = 31)
(d) Hydrochloric acid, HCl
(e) Nitric acid, HN O3

Question 22. What is the mass of—

(a) 1 mole of nitrogen atoms?
(b) 4 moles of aluminium atoms (Atomic mass of aluminium = 27)?
(c) 10 moles of sodium sulphite (Na2SO3)?

Question 23. Convert into mole.

(a) 12 g of oxygen gas
(b) 20 g of water
(c) 22 g of carbon dioxide.

Question 24. What is the mass of:

(a) 0.2 mole of oxygen atoms?
(b) 0.5 mole of water molecules?

Question 25. Calculate the number of molecules of sulphur (S8) present in 16 g of solid sulphur.

Question 26. Calculate the number of aluminium ions present in 0.051 g of aluminium oxide. (Hint: The mass of an ion is the same as that of an atom of the same element. Atomic mass of Al = 27 u)


Chapter 4 Structure of The Atom


Question 1. What are canal rays?

Question 2. If an atom contains one electron and one proton, will it carry any charge or not?

Question 3. On the basis of Thomson’s model of an atom, explain how the atom is neutral as a whole.

Question 4. On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom?

Question 5. Draw a sketch of Bohr’s model of an atom with three shells.

Question 6. What do you think would be the observation if the α-particle scattering experiment is carried out using a foil of a metal other than gold?  

Question 7. Write the distribution of electrons in carbon and sodium atoms.

Question 8. If K and L shells of an atom are full, then what would be the total number of electrons in the atom?

Question 9. How will you find the valency of chlorine, sulphur and magnesium?

Question 10. For the symbol H,D and T tabulate three sub-atomic particles found in each of them.

Question 12. Write the electronic configuration of any one pair of isotopes and isobars.

Question 13. Compare the properties of electrons, protons and neutrons.

Question 14. What are the limitations of J.J. Thomson’s model of the atom?

Question 15. What are the limitations of Rutherford’s model of the atom?

Question 16. Describe Bohr’s model of the atom.

Question 17. Compare all the proposed models of an atom given in this chapter.

Question 18. Summarise the rules for writing of distribution of electrons in various shells for the first eighteen elements.

Question 19. Define valency by taking examples of silicon and oxygen.

Question 20. Explain with examples

(i) Atomic number
(ii) Mass number
(iii) Isotopes
(iv) Isobars. Give any two uses of isotopes.

Question 21. Na+ has completely filled K and L shells. Explain.

Question 22. If bromine atom is available in the form of, say, two isotopes 79 35 Br (49.7%) and 81 35 Br (50.3%), calculate the average atomic mass of bromine atom.

Question 23. The average atomic mass of a sample of an element X is 16.2 u. What are the percentages of isotopes 16 8 X and 18 8 X in the sample?

Question 24. If Z = 3, what would be the valency of the element? Also, name the element.

Question 25. Composition of the nuclei of two atomic species X and Y are given as under X Y Protons = 6 6 Neutrons = 6 8 Give the mass numbers of X and Y. What is the relation between the two species?

Question 26. For the following statements, write T for True and F for False.

(a) J.J. Thomson proposed that the nucleus of an atom contains only nucleons.
(b) A neutron is formed by an electron and a proton combining together. Therefore, it is neutral.
(c) The mass of an electron is about 1 2000 times that of proton.
(d) An isotope of iodine is used for making tincture iodine, which is used as a medicine. Put tick () against correct choice and cross (×) against wrong choice in questions 15, 16 and 17

Question 27. Rutherford’s alpha-particle scattering experiment was responsible for the discovery of

(a) Atomic Nucleus
(b) Electron
(c) Proton
(d) Neutron

Question 28. Isotopes of an element have

(a) the same physical properties
(b) different chemical properties
(c) different number of neutrons
(d) different atomic numbers.

Question 29. Number of valence electrons in Cl– ion are:

(a) 16
(b) 8
(c) 17
(d) 18

Question 30. Which one of the following is a correct electronic configuration of sodium?

(a) 2,8
(b) 8,2,1
(c) 2,1,8
(d) 2,8,1.

Question 31. Complete the following table.


Chapter 5 The Fundamental Unit of Life


Question 1. Who discovered cells, and how?

Question 2. Why is the cell called the structural and functional unit of life?

Question 3. How do substances like CO2 and water move in and out of the cell? Discuss.

Question 4. Why is the plasma membrane called a selectively permeable membrane?  

Question 5. Fill in the gaps in the following table illustrating differences between prokaryotic and eukaryotic cells.

Question 6. Can you name the two organelles we have studied that contain their own genetic material?

Question 7. If the organisation of a cell is destroyed due to some physical or chemical influence, what will happen?

Question 8. Why are lysosomes known as suicide bags?

Question 9. Where are proteins synthesised inside the cell?

Question 10. Make a comparison and write down ways in which plant cells are different from animal cells.

Question 12. How is a prokaryotic cell different from a eukaryotic cell?

Question 13. What would happen if the plasma membrane ruptures or breaks down?

Question 14. What would happen to the life of a cell if there was no Golgi apparatus?

Question 15. Which organelle is known as the powerhouse of the cell? Why?

Question 16. Where do the lipids and proteins constituting the cell membrane get synthesised?

Question 17. How does an Amoeba obtain its food?

Question 18. What is osmosis?

Question 19. Carry out the following osmosis experiment: Take four peeled potato halves and scoos each one out to make potato cups. One of these potato cups should be made from a boiled potato. Put each potato cup in a trough containing water. Now,

(a) Keep cup A empty
(b) Put one teaspoon sugar in cup B
(c) Put one teaspoon salt in cup C
(d) Put one teaspoon sugar in the boiled potato cup D.

Keep these for two hours. Then observe the four potato cups and answer the following:
(i) Explain why water gathers in the hollowed portion of B and C.
(ii) Why is potato A necessary for this experiment?
(iii) Explain why water does not gather in the hollowed out portions of A and D.


Chapter 7 Diversity In Living Organisms


Question 1. Why do we classify organisms?

Question 2. Give three examples of the range of variations that you see in lifeforms around you

Question 3. Which do you think is a more basic characteristic for classifying organisms?

(a) The place where they live.
(b) The kind of cells they are made of. Why?

Question 4. What is the primary characteristic on which the first division of organisms is made?

Question 5. On what bases are plants and animals put into different categories?

Question 6. Which organisms are called primitive and how are they different from the so-called advanced organisms?

Question 7. Will advanced organisms be the same as complex organisms? Why?

Question 8. What is the criterion for classification of organisms as belonging to kingdom Monera or Protista?

Question 9. In which kingdom will you place an organism which is singlecelled, eukaryotic and photosynthetic?

Question 10. In the hierarchy of classification, which grouping will have the smallest number of organisms with a maximum of characteristics in common and which will have the largest number of organisms?

Question 11. Which division among plants has the simplest organisms?

Question 12. How are pteridophytes different from the phanerogams?

Question 13. How do gymnosperms and angiosperms differ from each other?

Question 14. How do poriferan animals differ from coelenterate animals?

Question 15. How do annelid animals differ from arthropods?

Question 16. What are the differences between amphibians and reptiles?

Question 17. What are the differences between animals belonging to the Aves group and those in the mammalia group?

Question 18. What are the advantages of classifying organisms?

Question 19. How would you choose between two characteristics to be used for developing a hierarchy in classification?

Question 20. Explain the basis for grouping organisms into five kingdoms.

Question 21. What are the major divisions in the Plantae? What is the basis for these divisions?

Question 22. How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals?

Question 23. Explain how animals in Vertebrata are classified into further subgroups.


Chapter 8 Motion


Question 1. An object has moved through a distance. Can it have zero displacement? If yes, support your answer with an example.

Question 2. A farmer moves along the boundary of a square field of side 10 m in 40 s. What will be the magnitude of displacement of the farmer at the end of 2 minutes 20 seconds?

Question 3. Which of the following is true for displacement?

(a) It cannot be zero.
(b) Its magnitude is greater than the distance travelled by the object.

Question 4. Distinguish between speed and velocity.

Question 5. Under what condition(s) is the magnitude of average velocity of an object equal to its average speed?

Question 6. What does the odometer of an automobile measure?

Question 7. What does the path of an object look like when it is in uniform motion?

Question 5. During an experiment, a signal from a spaceship reached the ground station in five minutes. What was the distance of the spaceship from the ground station? The signal travels at the speed of

Question 8. When will you say a body is in

(i) uniform acceleration?
(ii) nonuniform acceleration?

Question 9. A bus decreases its speed from 80 km h–1 to 60 km h–1 in 5 s. Find the acceleration of the bus.

Question 10. A train starting from a railway station and moving with uniform acceleration attains a speed 40 km h–1 in 10 minutes. Find its acceleration.

Question 11. What is the nature of the distance-time graphs for uniform and non-uniform motion of an object?

Question 12. What can you say about the motion of an object whose distance-time graph is a straight line parallel to the time axis?

Question 13. What can you say about the motion of an object if its speedtime graph is a straight line parallel to the time axis?

Question 14. What is the quantity which is measured by the area occupied below the velocity-time graph?

Question 15. A bus starting from rest moves with a uniform acceleration of 0.1 m s-2 for 2 minutes. Find

(a) The speed acquired,
(b) The distance travelled

Question 16. A train is travelling at a speed of 90 km h–1. Brakes are applied so as to produce a uniform acceleration of – 0.5 m s-2. Find how far the train will go before it is brought to rest.

Question 17. A trolley, while going down an inclined plane, has an acceleration of 2 cm s-2. What will be its velocity 3 s after the start?

Question 18. A racing car has a uniform acceleration of 4 m s-2. What distance will it cover in 10 s after start?

Question 19. A stone is thrown in a vertically upward direction with a velocity of 5 m s-1. If the acceleration of the stone during its motion is 10 m s–2 in the downward direction, what will be the height attained by the stone and how much time will it take to reach there?

Question 20. An athlete completes one round of a circular track of diameter 200 m in 40 s. What will be the distance covered and the displacement at the end of 2 minutes 20 s?

Question 21. Joseph jogs from one end A to the other end B of a straight 300 m road in 2 minutes 50 seconds and then turns around and jogs 100 m back to point C in another 1 minute. What are Joseph’s average speeds and velocities in jogging

(a) from A to B and
(b) from A to C?

Question 22. Abdul, while driving to school, computes the average speed for his trip to be 20 km h–1. On his return trip along the same route, there is less traffic and the average speed is 40 km h–1. What is the average speed for Abdul’s trip?

Question 23. A motorboat starting from rest on a lake accelerates in a straight line at a constant rate of 3.0 m s–2 for 8.0 s. How far does the boat travel during this time?

Question 24. A driver of a car travelling at 52 km h–1 applies the brakes and accelerates uniformly in the opposite direction. The car stops in 5 s. Another driver going at 3 km h–1 in another car applies his brakes slowly and stops in 10 s. On the same graph paper, plot the speed versus time graphs for the two cars. Which of the two cars travelled farther after the brakes were applied?


Chapter 9 Force and Laws of Motion


Question 1. Which of the following has more inertia:

(a) a rubber ball and a stone of the same size?
(b) a bicycle and a train?
(c) a fiverupees coin and a one-rupee coin?

Question 2. In the following example, try to identify the number of times the velocity of the ball changes: “A football player kicks a football to another player of his team who kicks the football towards the goal. The goalkeeper of the opposite team collects the football and kicks it towards a player of his own team”. Also identify the agent supplying the force in each case.

Question 3. Explain why some of the leaves may get detached from a tree if we vigorously shake its branch.

Question 4. Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?

Question 4. If action is always equal to the reaction, explain how a horse can pull a cart.

Question 5. Explain, why is it difficult for a fireman to hold a hose, which ejects large amounts of water at a high velocity.

Question 6. From a rifle of mass 4 kg, a bullet of mass 50 g is fired with an initial velocity of 35 m s–1. Calculate the initial recoil velocity of the rifle.

Question 7. Two objects of masses 100 g and 200 g are moving along the same line and direction with velocities of 2 m s–1 and 1 m s–1, respectively. They collide and after the collision, the first object moves at a velocity of 1.67 m s–1. Determine the velocity of the second object.

Question 8. An object experiences a net zero external unbalanced force. Is it possible for the object to be travelling with a non-zero velocity? If yes, state the conditions that must be placed on the magnitude and direction of the velocity. If no, provide a reason.

Question 9. When a carpet is beaten with a stick, dust comes out of it. Explain.

Question 10. Why is it advised to tie any luggage kept on the roof of a bus with a rope?

Question 11. A batsman hits a cricket ball which then rolls on a level ground. After covering a short distance, the ball comes to rest. The ball slows to a stop because

(a) the batsman did not hit the ball hard enough.
(b) velocity is proportional to the force exerted on the ball.
(c) there is a force on the ball opposing the motion.
(d) there is no unbalanced force on the ball, so the ball would want to come to rest.

Question 12. A truck starts from rest and rolls down a hill with a constant acceleration. It travels a distance of 400 m in 20 s. Find its acceleration. Find the force acting on it if its mass is 7 metric tonnes (Hint: 1 metric tonne = 1000 kg.)

Question 13. A stone of 1 kg is thrown with a velocity of 20 m s–1 across the frozen surface of a lake and comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice?

Question 14. A 8000 kg engine pulls a train of 5 wagons, each of 2000 kg, along a horizontal track. If the engine exerts a force of 40000 N and the track offers a friction force of 5000 N, then calculate:

(a) the net accelerating force
(b) the acceleration of the train
(c) the force of wagon 1 on wagon 2.

Question 15. An automobile vehicle has a mass of 1500 kg. What must be the force between the vehicle and road if the vehicle is to be stopped with a negative acceleration of 1.7 m s–2?

Question 16. What is the momentum of an object of mass m, moving with a velocity v?

(a) (mv)2
(b) mv2
(c) ½ mv2
(d) mv

Question 17. Using a horizontal force of 200 N, we intend to move a wooden cabinet across a floor at a constant velocity. What is the friction force that will be exerted on the cabinet?

Question 18. Two objects, each of mass 1.5 kg, are moving in the same straight line but in opposite directions. The velocity of each


Chapter 10 Gravitation


Question 1. State the universal law of gravitation.

Question 2. Write the formula to find the magnitude of the gravitational force between the earth and an object on the surface of the earth.

Question 3. What do you mean by free fall?

Question 4. What do you mean by acceleration due to gravity?

Question 5. What are the differences between the mass of an object and its weight?

Question 6. Why is the weight of an object on the moon 1 6 th its weight on the earth?

Question 7. Why is it difficult to hold a school bag having a strap made of a thin and strong string?

Question 8. What do you mean by buoyancy?

Question 9. Why does an object float or sink when placed on the surface of water?

Question 10. You find your mass to be 42 kg on a weighing machine. Is your mass more or less than 42 kg?

Question 11. You have a bag of cotton and an iron bar, each indicating a mass of 100 kg when measured on a weighing machine. In reality, one is heavier than other. Can you say which one is heavier and why?

Question 12. How does the force of gravitation between two objects change when the distance between them is reduced to half ?

Question 13. Gravitational force acts on all objects in proportion to their masses. Why then, a heavy object does not fall faster than a light object?

Question 14. What is the magnitude of the gravitational force between the earth and a 1 kg object on its surface? (Mass of the earth is 6 × 1024 kg and radius of the earth is 6.4 × 106 m.)

Question 15. The earth and the moon are attracted to each other by gravitational force. Does the earth attract the moon with a force that is greater or smaller or the same as the force with which the moon attracts the earth? Why?

Question 16. If the moon attracts the earth, why does the earth not move towards the moon?

Question 17. What happens to the force between two objects, if

(i) the mass of one object is doubled?
(ii) the distance between the objects is doubled and tripled?
(iii) the masses of both objects are doubled?

Question 18. What is the importance of universal law of gravitation?

Question 19. What is the acceleration of free fall?

Question 20. What do we call the gravitational force between the earth and an object?

Question 21. Amit buys few grams of gold at the poles as per the instruction of one of his friends. He hands over the same when he meets him at the equator. Will the friend agree with the weight of gold bought? If not, why? [Hint: The value of g is greater at the poles than at the equator.]

Question 22. Why will a sheet of paper fall slower than one that is crumpled into a ball?

Question 23. Gravitational force on the surface of the moon is only 1 6 as strong as gravitational force on the earth. What is the weight in newtons of a 10 kg object on the moon and on the earth?

Question 24. A ball is thrown vertically upwards with a velocity of 49 m/s. Calculate

(i) the maximum height to which it rises,
(ii) the total time it takes to return to the surface of the earth.

Question 25. A stone is released from the top of a tower of height 19.6 m. Calculate its final velocity.

Question 26. A stone is thrown vertically upward with an initial velocity of 40 m/s. Taking g = 10 m/s2, find the maximum height reached by the stone. What is the net displacement and the total distance covered by the stone?

Question 27. Calculate the force of gravitation between the earth and the Sun, given that the mass of the earth = 6 × 1024 kg and of the Sun = 2 × 1030 kg. The average distance between the two is 1.5 × 1011 m.

Question 28. A stone is allowed to fall from the top of a tower 100 m high and at the same time another stone is projected vertically upwards from the ground with a velocity of 25 m/s. Calculate when and where the two stones will meet.

Question 29. A ball thrown up vertically returns to the thrower after 6 s. Find

(a) the velocity with which it was thrown up,
(b) the maximum height it reaches, and
(c) its position after 4 s.

Question 30. In what direction does the buoyant force on an object immersed in a liquid act?

Question 31. Why does a block of plastic released under water come up to the surface of water?

Question 32. The volume of 50 g of a substance is 20 cm3. If the density of water is 1 g cm–3, will the substance float or sink?

Question 33. The volume of a 500 g sealed packet is 350 cm3. Will the packet float or sink in water if the density of water is 1 g cm–3? What will be the mass of the water displaced by this packet?


Chapter 11 Work And Energy


Question 1. A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force (Fig. 11.3). Let us take it that the force acts on the object through the displacement. What is the work done in this case?

Question 1. When do we say that work is done?

Question 2. Write an expression for the work done when a force is acting on an object in the direction of its displacement.

Question 3. Define 1 J of work.

Question 4. A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is
done in ploughing the length of the field?

Question 1. What is the kinetic energy of an object?

Question 2. Write an expression for the kinetic energy of an object.

Question 3. The kinetic energy of an object of mass, m moving with a velocity of 5 m s–1 is 25 J. What will be its kinetic energy when its velocity is doubled? What will be its kinetic energy when its velocity is increased three times?

Question 1. What is power?

Question 2. Define 1 watt of power.

Question 3. A lamp consumes 1000 J of electrical energy in 10 s. What is its power?

Question 4. Define average power.

Question 1. Look at the activities listed below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.

  •  Suma is swimming in a pond.

  •  A donkey is carrying a load on its back.

  •  A wind-mill is lifting water from a well.

  •  A green plant is carrying out photosynthesis

  •  An engine is pulling a train.

  •  Food grains are getting dried in the sun.

  •  A sailboat is moving due to wind energy.

Question 2. An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object?

Question 3. A battery lights a bulb. Describe the energy changes involved in the process.

Question 4. Certain force acting on a 20 kg mass changes its velocity from 5 m s–1 to 2 m s–1. Calculate the work done by the force.

Question 5. A mass of 10 kg is at a point A on a table. It is moved to a point B. If the line joining A and B is horizontal, what is the work done on the object by the gravitational force? Explain your answer.

Question 6. The potential energy of a freely falling object decreases progressively. Does this violate the law of conservation of energy? Why?

Question 7. What are the various energy transformations that occur when you are riding a bicycle?

Question 8. Does the transfer of energy take place when you push a huge rock with all your might and fail to move it? Where is the energy you spend going?

Question 9. A certain household has consumed 250 units of energy during a month. How much energy is this in joules?

Question 10. An object of mass 40 kg is raised to a height of 5 m above the ground. What is its potential energy? If the object is allowed to fall, find its kinetic energy when it is half-way down.

Question 11. What is the work done by the force of gravity on a satellite moving round the earth? Justify your answer.

Question 12. Can there be displacement of an object in the absence of any force acting on it? Think. Discuss this question with your friends and teacher.

Question 13. A person holds a bundle of hay over his head for 30 minutes and gets tired. Has he done some work or not? Justify your answer.

Question 14. An electric heater is rated 1500 W. How much energy does it use in 10 hours?

Question 15. Illustrate the law of conservation of energy by discussing the energy changes which occur when we draw a pendulum bob to one side and allow it to oscillate. Why does the bob eventually come to rest? What happens to its energy eventually? Is it a violation of the law of conservation of energy?

Question 16. An object of mass, m is moving with a constant velocity, v. How much work should be done on the object in order to bring the object to rest?

Question 17. Calculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km/h?

Question 18. In each of the following a force, F is acting on an object of mass, m. The direction of displacement is from west to east shown by the longer arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero.

Question 19. Soni says that the acceleration in an object could be zero even when several forces are acting on it. Do you agree with her? Why?

Question 20. Find the energy in kW h consumed in 10 hours by four devices of power 500 W each.

Question 21. A freely falling object eventually stops on reaching the ground. What happenes to its kinetic energy?


Chapter 12 Sound


Question 1. Explain how sound is produced by your school bell.

Question 2. Why are sound waves called mechanical waves?

Question 3. Suppose you and your friend are on the moon. Will you be able to hear any sound produced by your friend?

Question 4. Which wave property determines (a) loudness, (b) pitch?

Question 5. Guess which sound has a higher pitch: guitar or car horn?

Question 6. What are wavelength, frequency, time period and amplitude of a sound wave?

Question 7. How are the wavelength and frequency of a sound wave related to its speed?

Question 8. Calculate the wavelength of a sound wave whose frequency is 220 Hz and speed is 440 m/s in a given medium.

Question 9. A person is listening to a tone of 500 Hz sitting at a distance of 450 m from the source of the sound. What is the time interval between successive compressions from the source?

Question 10. In which of the three media, air, water or iron, does sound travel the fastest at a particular temperature?

Question 11. An echo returned in 3 s. What is the distance of the reflecting surface from the source, given that the speed of sound is 342 m s–1?

Question 12. Why are the ceilings of concert halls curved?

Question 13. What is the audible range of the average human ear?

Question 14. What is the range of frequencies associated with (a) Infrasound? (b) Ultrasound?

Question 15. A submarine emits a sonar pulse, which returns from an underwater cliff in 1.02 s. If the speed of sound in salt water is 1531 m/s, how far away is the cliff?

Question 16. What is sound and how is it produced?

Question 17. Describe with the help of a diagram, how compressions and rarefactions are produced in air near a source of sound.

Question 18. Cite an experiment to show that sound needs a material medium for its propagation.

Question 19. Why is sound wave called a longitudinal wave?

Question 20. Which characteristic of the sound helps you to identify your friend by his voice while sitting with others in a dark
room?

Question 21. Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen, why?

Question 22. A person has a hearing range from 20 Hz to 20 kHz. What are the typical wavelengths of sound waves in air corresponding to these two frequencies? Take the speed of sound in air as 344 m s–1.

Question 23. Two children are at opposite ends of an aluminium rod. One strikes the end of the rod with a stone. Find the ratio of times taken by the sound wave in air and in aluminium to reach the second child.

Question 24. The frequency of a source of sound is 100 Hz. How many times does it vibrate in a minute?

Question 25. Does sound follow the same laws of reflection as light does? Explain.

Question 26. When a sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound production remains the same. Do you hear echo sound on a hotter day?

Question 27. Give two practical applications of reflection of sound waves.

Question 28. A stone is dropped from the top of a tower 500 m high into a pond of water at the base of the tower. When is the splash heard at the top? Given, g = 10 m s–2 and speed of sound = 340 m s–1.

Question 29. A sound wave travels at a speed of 339 m s–1. If its wavelength is 1.5 cm, what is the frequency of the wave? Will it be audible?

Question 30. What is reverberation? How can it be reduced?

Question 31. What is loudness of sound? What factors does it depend on?

Question 32. Explain how bats use ultrasound to catch a prey.

Question 33. How is ultrasound used for cleaning?

Question 34. Explain the working and application of a sonar.

Question 35. A sonar device on a submarine sends out a signal and receives an echo 5 s later. Calculate the speed of sound in water if the distance of the object from the submarine is 3625 m.

Question 36. Explain how defects in a metal block can be detected using ultrasound.

Question 37. Explain how the human ear works.


Chapter 13 Why Do We Fall Ill


Question 1. State any two conditions essential for good health.

Question 2. State any two conditions essential for being free of disease.

Question 3. Are the answers to the above questions necessarily the same or different? Why? 

Question 4. List any three reasons why you would think that you are sick and ought to see a doctor. If only one of these symptoms were present, would you still go to the doctor? Why or why not?

Question 5. In which of the following case do you think the long-term effects on your health are likely to be most unpleasant?

  •  if you get jaundice,

  •  if you get lice,

  •  if you get acne. Why?

Question 6. Why are we normally advised to take bland and nourishing food when we are sick?

Question 7. What are the different means by which infectious diseases are spread?

Question 8. What precautions can you take in your school to reduce the incidence of infectious diseases?

Question 9. What is immunisation?

Question 10. What are the immunisation programmes available at the nearest health centre in your locality?

Question 11. How many times did you fall ill in the last one year? What were the illnesses?

(a) Think of one change you could make in your habits in order to avoid any of/most of the above illnesses.
(b) Think of one change you would wish for in your surroundings in order to avoid any of/most of the above illnesses.

Question 12. A doctor/nurse/health-worker is exposed to more sick people than others in the community. Find out how she/he avoids getting sick herself/himself.

Question 13. Conduct a survey in your neighbourhood to find out what the three most common diseases are. Suggest three steps that could be taken by your local authorities to bring down the incidence of these diseases.

Question 14. A baby is not able to tell her/his caretakers that she/he is sick. What would help us to find out

(a) that the baby is sick?
(b) what is the sickness?

Question 15. Under which of the following conditions is a person most likely to fall sick?

(a) when she is recovering from malaria.
(b) when she has recovered from malaria and is taking care of someone suffering from chicken-pox.
(c) when she is on a four-day fast after recovering from malaria and is taking care of someone suffering from chicken-pox. Why?

Question 16. Under which of the following conditions are you most likely to fall sick?

(a) when you are taking examinations.
(b) when you have travelled by bus and train for two days.
(c) when your friend is suffering from measles. Why?


Chapter 14 Natural Resources


Question 1. How is our atmosphere different from the atmospheres on Venus and Mars?

Question 2. How does the atmosphere act as a blanket?

Question 3. What causes winds?

Question 4. How are clouds formed?

Question 5. List any three human activities that you think would lead to air pollution.

Question 6. Why do organisms need water?

Question 7. What is the major source of fresh water in the city/town/village where you live?

Question 8. Do you know of any activity which may be polluting this water source?

Question 9. How is soil formed?

Question 10. What is soil erosion?

Question 11. What are the methods of preventing or reducing soil erosion?

Question 12. What are the different states in which water is found during the water cycle?

Question 13. Name two biologically important compounds that contain both oxygen and nitrogen.

Question 14. List any three human activities which would lead to an increase in the carbon dioxide content of air.

Question 15. What is the greenhouse effect?

Question 16. What are the two forms of oxygen found in the atmosphere?


Chapter 15 Improvement In Food Resources


Question 1. What do we get from cereals, pulses, fruits and vegetables?

Question 2. How do biotic and abiotic factors affect crop production?

Question 3. What are the desirable agronomic characteristics for crop improvements?

Question 4. What are macro-nutrients and why are they called macronutrients?

Question 5. How do plants get nutrients?

Question 6. Compare the use of manure and fertilizers in maintaining soil fertility.

Question 7. Which of the following conditions will give the most benefits? Why?

(a) Farmers use high-quality seeds, do not adopt irrigation or use fertilizers.
(b) Farmers use ordinary seeds, adopt irrigation and use fertilizer.
(c) Farmers use quality seeds, adopt irrigation, use fertilizer and use crop protection measures.

Question 8. Why should preventive measures and biological control methods be preferred for protecting crops?

Question 9. What factors may be responsible for losses of grains during storage?

Question 10. Which method is commonly used for improving cattle breeds and why?

Question 11. What management practices are common in dairy and poultry farming?

Question 12. What are the differences between broilers and layers and in their management?

Question 13. Discuss the implications of the following statement: “It is interesting to note that poultry is India’s most efficient converter of low fibre food stuff (which is unfit for human consumption) into highly nutritious animal protein food.”

Question 14. How are fish obtained?

Question15. What are the advantages of composite fish culture?

Question 16. What are the desirable characters of bee varieties suitable for honey production?

Question 17. What is pasturage and how is it related to honey production?

Question 18. Explain any one method of crop production which ensures high yield.

Question 19. Why are manure and fertilizers used in fields?

Question 20. What are the advantages of inter-cropping and crop rotation?

Question 21. What is genetic manipulation? How is it useful in agricultural practices?

Question 22. How do storage grain losses occur?

Question 23. How do good animal husbandry practices benefit farmers?

Question 24. What are the benefits of cattle farming?

Question 25. For increasing production, what is common in poultry, fisheries and bee-keeping?

Question 26. How do you differentiate between capture fishing, mariculture and aquaculture?


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