Class XII Sub Physics U I Electrostatics and U II Current Electricity Date 19.10.2021
MM 20 ALL QUESTIONS ARE MULTIPLE CHOICE TYPE CARRYING 1 MARK EACH Time 1hr
Knowledge Based Questions:
1. The dielectric constant of an insulator cannot be:
- (a) 3.5
- (b) 2
- (c) 4.2
- (d) ∞
2. Which of the following is responsible for the conduction of electricity in metallic solids?
- (a) Free electrons
- (b) Anion and Cation
- (c) Electron-hole pair
- (d) Ionised particle
3. Objects may acquire an excess or deficiency of charge by:
- (a) Hammering
- (b) Heating
- (c) Shaking
- (d) Rubbing
4. 1 Volt is equivalent to:
- (a) N`C^{-1}`
- (b) N`S^{-1}`
- (c) J`S^{-1}`
- (d) joule/coulomb
5. Work done in bringing a unit positive charge from infinity to a point is :
- (a) Potential Energy
- (b) Electrostatic potential
- (c) Electric field
- (d) Work
6. For system of charges, the total potential at a point depends upon:
- (a) Charges
- (b) position of point with respect to charges
- (c) nature of medium
- (d) All of the above.
7. Kirchhoff’s current law at a junction deals with conservation of :
- (a) Charge
- (b) Energy
- (c) Momentum
- (d) All of these
Understanding Based Questions:
8. Lightening is an electrical discharge caused by imbalance between:
- (a) Clouds and the ground
- (b) Within the clouds
- (c) Both a and b
- (d) None of these
9. The electrical resistance of metals :
- (a) increases with an increase in temperature
- (b) decreases with an increase in temperature
- (c) is independent of temperature
- (d) none of the above
10. The unit of electric power is :
- (a) Watt
- (b) volt
- (c) Kilowatt-hour
- (d) ampere
11. When some charge is transferred to ‘A’, It is readily gets distributed over the entire surface of ‘A’. If some charge is put on ‘B’, it stays at the same place. Here, A and B refer to:
- (a)Insulator, Conductor
- (b) Conductor, Insulator
- (c) Insulator, Insulator
- (d) Conductor, Conductor
12. Two charges +q and –q are situated at a certain distance. At the point exactly midway between them
- (a) electric field is zero
- (b) electric field not zero
- (c) electric potential not zero
- (d) none of these
13. The algebraic sum of all currents meeting at any point in an electrical circuit is
- (a)Infinite
- (b) Positive
- (c) Zero
- (d) Negative
14. The length and area of cross-section of a metal wire of resistance R are doubled, then new resistance R' is:
- (a) R' = R
- (b) R' = 4R
- (c) R' = 1/4R
- (d) R' = 2R
15. When a dielectric material is introduced between the plates of a charged condenser then electric field between the plates:
- (a) Decreases
- (b) Increases
- (c) Remain constant
- (d) First increase then decrease
16. You are travelling in a car during a thunder storm. In order to protect yourself from lightening, would you prefer to:
- (a) Remain in the car
- (b) Take shelter under a tree
- (c) Get out and be flat on the ground
- (d) Touch the nearest electric pole
Application Based Questions:
17. Four charges each of 5 μC are placed at the four corners of a square of side 10 cm. What is the electric field at the centre of square?
- (a) 4500 V
- (b) 4500√2 V
- (c) 180 x `10^{4}` √2V
- (d) Zero
18. How much work is required to carry a 6 micro coulomb charge from the negative to the positive terminal of a 9 V battery?
- (a) 54×`10^{-3}`J
- (b) 54×`10^{-9}` J
- (c) 54×`10^{-6}` J
- (d) 54×`10^{-12}` J
19. The resistance of each arm of the wheat stone bridge is 10 ohm. A resistance of 10 ohm is connected in series with the galvanometer. Then equivalent resistance across the battery will be:
- (a) 20 ohm
- (b) 40 ohm
- (c) 15 ohm
- (d) 10 ohm
20. A cell of emf 1.5 volt given a balance point 30 cm length of potentiometer wire.For another cell, the balance point shifts to 50 cm.The emf of second cell will be
- (a)2.0 Volt
- (b)2.5 Volt
- (c)1.5 Volt
- (d) None of these
