| (Download) CBSE Class-12 Sample Paper 2019-20 : Operation And Maintenance Of Communication Devices Posted: 25 Sep 2019 12:24 AM PDT (Download) CBSE Class-12 Sample Paper 2019-20 : Operation And Maintenance Of Communication Devices Class: XII
Operation And Maintenance Of Communication Devices-(789)
Sample Question Paper 2019-20 SECTION–A Answer any 10 questions out of the given 12 questions:
1. The frequency range of 300KHz to 3000KHz is known as
(a) Low frequency
(b) Medium frequency
(c) High Frequency
(d) Very High frequency
2. Noise is added to a signal in a communication system
(a) At the receiving end
(b) At transmitting end
(c) In the channel
(d) During regeneration of the information
3. A transponder is a satellite equipment which
(a) Receives the signal from earth station and amplifies it
(b) Changes the frequency of received signal
(c) Retransmits the received signal
(d) All of the above
4. The quality of space link is measured in terms of_ ratio
(a) C/N
(b) S/N
(c) G/T
(d) EIRP
5. CDMA rejects
(a) Narrow band interference
(b) Wideband interference
(c) Both A and B
(d) None of the above.
6. Which type of PCB requires minimum soldering on component side in order to avoid replacement oriented difficulties ?
(a) Single sidedPCB
(b) Double sidedPCB
(c) Both a and b
(d) None of the above
7. Which of the following is not a virus in mobile phone ?
(a) Trojan Horse
(b) Fake android apps
(c) spyware
(d) Avast
8. The maximum allocated frequency deviation in FM is
(a) 10MHz
(b) 75MHz
(c) 100MHz
(d) 125MHz
9. In digital modulation
(a) Carrier Signal is digital and message signal is analog
(b) Message signal is digital and carrier signal is analog
(c) Both carrier and message signals are digital
(d) Both carrier and message signals are analog
10. WiFi stands for
(a) Wireless fidelity
(b) Wideband function
(c) wireless function
(d) None of the above.
11. IMT2000 is a digital mobile system that function as
(a) Pager
(b) Cordless
(c) Low earth orbit satellites
(d) All of theabove.
12. CDMA offers
(a) Soft handoff
(b) Hard Handoff
(c) Hanofff varies from cell to cell
(d) None of the above 
Courtesy: CBSE  |
| (Download) CBSE Class-12 Sample Paper 2019-20 : Electrical Appliances Posted: 25 Sep 2019 12:15 AM PDT (Download) CBSE Class-12 Sample Paper 2019-20 : Electrical Appliances Class: XII
Electrical Appliances-(788)
Sample Question Paper 2019-20 SECTION–A Answer any 10 questions out of the given 12 questions:
1. Which among these is the application of universal motors?
(a) Vacuumcleaners
(b) Fans
(c) Hairdryers
(d) Washingmachines
2. What is the typical value of the capacitor used in ‘capacitor start capacitor run’ single phase induction motor?
(a) 5 μ F
(b) 40 μ F
(c) 300 μ F
(d) 1000 μ F
3. Which timer is used in fully automatic washing machines?
(a) Electricaltimer
(b) Electronictimer
(c) Mechanicaltimer
(d) Springtimer
4. What is the first equipment placed in the Uninterrupted Power Supply (UPS)?
(a) Inverter
(b) Battery
(c) Rectifier
(d) Any ofthese
5. The heating element in an electric iron is usually made of
(a) brass.
(b) iron.
(c) nichrome.
(d) platinum.
6. Which type of magnet is used in an electric bell?
(a) Temporarymagnet
(b) Permanentmagnet.
(c) Electromagnet.
(d) Carbonmagnet
7. Which of the following gas is mainly used inside an electric bulb?
(a) Carbon dioxidegas.
(b) Hydrogengas.
(c) Inert gas.
(d) Heliumgas.
8. Type of single phase motor having highest power factor at full load is
(a) Shaded poletype
(b) Capacitorrun
(c) Capacitorstart
(d) Singlephase
9. Which of the following motors is used in hair dryer?
(a) Synchronousmotor
(b) Shaded pole inductionmotor
(c) Split phase
(d) Cage inductionmotor
10. What type of dielectric material is used in capacitorsused for fans and for power factor correction?
(a) Oil impregnated paper
(b) Vacuum
(c) Glass
(d) Mica
11. If field current is decreased in shunt dc motor, the speed of the motor
(a) Decrease
(b) Increase
(c) Remains same
(d) None of theabove
12. What creates washing action in washing machine?
(a) energy
(b) watersupply
(c) turbulence
(d) Electricity
Courtesy: CBSE  |
| (Download) CBSE Class-12 Sample Paper 2019-20 : Electrical Machines Posted: 24 Sep 2019 11:29 PM PDT (Download) CBSE Class-12 Sample Paper 2019-20 : Electrical Machines Class: XII
Electrical Machines-(787)
Sample Question Paper 2019-20 SECTION–A Answer any 10 questions out of the given 12 questions:
1. Which motor cannot be started on no load?
(a) Series Motor
(b) Shunt motor
(c) Cumulative compound motor
(d) Both b and c.
2. Which of the following motor has negative speed regulation?
(a) Seriesmotor
(b) Stunt motor
(c) Cumulative compoundmotor
(d) Differential compoundmotor
3. Core of transformer is laminated to
(a) Reduce hysteresislosses
(b) Eddy currentlosses
(c) Copperlosses
(d) All of theabove
4. A transformertransforms
(a) Power factor
(b) Voltage
(c) Power
(d) Energy 5. Natural oil cooling is used in transformer upto a rating of
(a) 3000 kVA
(b) 1000 kVA
(c) 500 kVA
(d) 250 kVA
6. Soldering iron is made of wedge shape in order to......
(a) Apply high pressure atedge
(b) Retainheat
(c) Retainsolder
(d) Forge welding
7. The purpose of using flux in soldering is to.......
(a) Increase fluidity of soldermetal
(b) Feel up gaps left in a badjoint
(c) Carbonsteel
(d) Prevent oxidesforming
8. The starting torque of a capacitor start motor is
(a) zero
(b) low
(c) same as ratedtorque
(d) more than ratedtorque.
9. A universal motor is one
(a) which can run on any value of supplyvoltage
(b) which has infinitely varyingspeed
(c) which can operate on ac as well as dc voltage
(d) which can work as single phase or three phasemotor.
10. The motor used in household refrigerators is
(a) dc seriesmotor
(b) dc shuntmotor
(c) universalmotor
(d) single phase inductionmotor.
11. The direction of rotation of universal motor can be reversed by
(a) reversing the supplyterminals
(b) switching over from ac todc
(c) interchanging the brushleads
(d) any of theabove.
12. In an induction motor, rotor speed is always
(a) Less than the statorspeed
(b) More than the statorspeed
(c) Equal to the statorspeed
(d) None ofthese
Very Short Questions: (2 marks each).
Answer any 5 questions out of the given 7 questions:
13. How is speed control of dc motor achieved?
14. What are the functions of poles in dc motors?
15. What are characteristics of capacitor start motor?
16. What are different types of solder?
17. Give winding details of fractional horse power motor?
18. What are the causes of faults in ac motor?
19. List applications of voltage and current transformer. Short Questions: (3 marks each).
Answer any 5 questions out of the given 7 questions:
20. What is single phase repulsion motor? Also write various applications of single phase motor?
21. Describe the construction of starters used to start a three-phase slip-ring induction motor.
22. Explain the construction and working principle of compound motor with a neat schematic diagram.
23. Explain testing, fault finding and repairing of dc motor.
24. Describe working principle of Shunt motor. Also give the differences between series and shunt motor.
25. Draw and explain step up and step down transformers.
26. Give construction details and winding details of shaded pole motor. SECTION –B Long/Essay type questions (5 marks each).
Answer any 1 question out of the given 2questions:
27. What are various soldering techniques? Explain in details.
28. Classify AC motors. Explain principle of operation, construction and characteristics of Universal Motor.
Courtesy: CBSE  |
| (Download) CBSE Class-12 Sample Paper 2019-20 : Insurance Posted: 24 Sep 2019 10:35 PM PDT (Download) CBSE Class-12 Sample Paper 2019-20 : Insurance Class: XII
Insurance-(786)
Sample Question Paper 2019-20 SECTION–A Answer any 10 questions out of the given 12 questions:
1. State the term used to provide the coverage for the potential financial loss for a feeor consideration.
2. Name the documents that are accepted as age proof ininsurance.
3. „Automotive Insurance‟ is generally referred toas
4. State one point of difference between Robbery and Burglary.
5. In which year does the General Insurance business was nationalized?
6. The Insurance that provides protection against loss of freight is called Insurance.
7. Under CIFcontracts,the seller is responsible for arranging the & delivering the goods at port of destination.
I. Vehicle
II. Ferry
III. Crane
IV. Ship
8. Senior Citizen Mediclaim policy is available to a resident in India between the ge of 60 & 80 years. If renewed without break, the cover can be continued upto the age of .
9. Mediclaim Insurance was primarily introduced to cover charges.
I. Insurance
II. Hospitalization
III. Nursing
IV. Accident
10. In policy, a fixed amount is paid as compensation irrespective of theloss.
I. Valued
II. Fixed
III. Mandatory
IV. Legal
11. What is Fire Insurance?
12. For what period are fire insurance policiesissued?
Courtesy: CBSE  |
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