INDIA EXAMINATIONS: CBSE PORTAL : “(Download) CBSE: Class XII Mathematics Question Paper

Monday, August 3, 2020

CBSE PORTAL : “(Download) CBSE: Class XII Mathematics Question Paper - 2020” plus 1 more

(Download) CBSE: Class XII Mathematics Question Paper - 2020

Posted: 03 Aug 2020 03:50 AM PDT

Question Papers For Board Examinations 2020

Class – XII

Subject – Mathematics

Subject :- Physics
Class : XII
Year : 2020

General Instructions :
Read the following instructions very carefully and strictly follow them :
(i) This question paper comprises four sections  A, B, C and D. There are 34 questions in the question paper. All questions are compulsory.
(ii) Section A comprises of 20 questions of 1 mark each.
(iii) Section B comprises of 5 questions of 2 marks each.
(iv) Section C comprises of 5 questions of 4 marks each.
(v) Section D comprises of 4 questions of 5 marks each.
(vi) There is no overall choice in the question paper. However, an internal choice has been provided in 3 questions of one mark, 2 questions of two marks,

2 questions of four marks and 2 questions of five marks. Only one of the choices in such questions have to be attempted.
(vii) In addition to this, separate instructions are given with each section and question, wherever necessary.
(viii) Use of calculator is not permitted.

SECTION A

Note : Question numbers 1 to 10 are multiple choice type questions. Select the correct option.
1. Three unbiased coins are tossed. What is the probability of getting at most two tails ? 1
(A) 8/1
(B) 8/3
(C) 8/5
(D) 7/5

2. In a single throw of a pair of dice, the number of elements in the event of getting the sum as 8 on them is 1
(A) 6
(B) 5
(C) 4
(D) 3

3. The ordinate of the point on y-axis, which is equidistant from (– 4, 1) and
(2, 3) is 1
(A) 2
(B) 1
(C) – 1
(D) – 2

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CBSE Board Class-XII

सीबीएसई बोर्ड कक्षा-10

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Class-12

(Download) CBSE: Class XII Physics Question Paper - 2020

Posted: 03 Aug 2020 03:16 AM PDT

Question Papers For Board Examinations 2020

Class – XII

Subject – Physics

Subject :- Physics
Class : XII
Year : 2020

1. (a) Define electric field intensity. Give its SI unit. Write the formula for electric field intensity due to a point charge. Calculate the electric field intensity at a distance of 50 cm from a charge of 50 C. 5

(b) What is a capacitor ? Derive a formula for the energy stored in a capacitor. 5
OR
Draw a figure showing the combination of three capacitors in series. Write the formula for the net capacitance when three capacitors are connected in series. Three capacitors of 2 F, 3 F and 6 F are connected in series. Find the net capacitance. 5

2. (a) Define magnetic field. Write the SI unit of magnetic field intensity.
Write the formula for the magnetic field intensity due to a straight current-carrying conductor. What is the value of the magnetic field at the surface of the conductor ? 5
(b) What are the factors that affect the force on a charge moving in a magnetic field ? Write the formula for the force. State the cases when the charge will experience (i) maximum, and (ii) minimum force. 5
OR
Define the terms Magnetic flux density and Permeability. Write their SI units. Write the name of a substance having large permeability. 5
(c) Derive an expression for the magnetic field intensity at the centre of a current-carrying circular coil.

3. (a) Define nuclear fission and nuclear fusion. Give three differences between them. 5
(b) What are radio-isotopes ? Write the name of two radio-iostopes and write one use of each. 5
OR
What are radiation hazards ? Name two radiation hazards. How can we protect ourselves from radiation hazards ? 5
(c) Explain the principle, construction and working of a nuclear reactor. 5
4. (a) What are semiconductors ? Give the atomic structure of Ge and Si.
How is the conductivity of semiconductors affected by rise in temperature ? 5
(b) Draw the symbol of p-n junction. Draw a circuit diagram of p-n junction in forward biasing. Explain the working of a p-n junction in forward biasing. 5 OR
What is a rectifier ? Explain the working of a p-n junction as a full-wave rectifier. 5
(c) Draw a symbol of an n-p-n transistor. Draw a circuit diagram of n-p-n transistor with proper biasing and explain transistor action. 5