12th physics chapter 2 objective questions in english

1. Two capacitors, each of capacitance C, are connected in series. Their equivalent capacitance is

(a) 2C 

(b) C

(c) C / 2

(d) 1 / 2C

Answer (c) C / 2

2. If there are several capacitors available, for getting maximum capacitance, these should be connected in

(a) series 

(b) parallel

(c) mixed grouping

(d) None of these

Answer (b) parallel

3. When a thin mica sheet is placed between the plates of a parallel plate capacitor, the capacitance

(a) increases slightly

(b) decreases

(c) remains the same

(d) None of these

Answer (a) increases slightly

4. Two capacitors each of capacitance 1 μF are connected in parallel and a third capacitor of 0.5 μF is connected in series with this combination. The resulting capacitance will be 

(a) 16 μF

(b) 10 F

(c) 2.5 μF

(d) 12 μF

Answer (c) 2.5 μF

5. The value of dielectric constant of a substance except air is always greater than 

(a) zero

(b) 0.5

(c) 1

(d) 2

Answer (c) 1

6. Eight drops each of radius r and charge q are merged to form a single drop. The ratio of the potential of big drop to small drop is

(a) 8:1

(b) 4:1

(c) 2:1

(d) 1:8

Answer (b) 4:1

7. If a metal rod is inserted between the plates of a capacitor connecting them, the capacitance will become

(a) zero

(b) infinity

(c) 9 x 10⁹ μF

(d) None of these 

Answer (b) infinity

8. The electric potential due to a small electric dipole at a large distance r from the center of the dipole is proportional to

(a) r

(b) 1 / r

(c) 1 / r²

(d) 1 / r³

Answer (c) 1 / r²

9. If uniform electric field exists along Z-axis, equipotential is along

(a) XY-plane

(b) XZ-plane

(c) YZ-plane

(d) anywhere 

Answer (a) XY-plane

10. Eight drops each of radius r and charge q are merged to form a big drop. The potential energy of the big drop as compared to one small drop is

(a) 32 times 

(b) 16 times

(c) 8 times 

(d) 4 times 

Answer (a) 32 times 

11. A spherical conductor is charged. The electric field intensity at its centre will be

(a) infinite 

(b) zero

(c) equal to that at the surface

(d) None of these 

Answer (b) zero

12. The capacitance of a parallel plate capacitor by the introduction of a dielectric between the plates of the capacitor

(a) increases 

(b) decreases

(c) remains same

(d) nothing can be said

Answer (a) increases 

13. The loss of energy taking place due to sharing of charge between two conductors depends upon

(a) potential difference

(b) square of potential difference

(c) capacitance

(d) l2

Answer (b) square of potential difference

14. A hollow metallic sphere of radius 5 cm is charged to 10 volt. The potential at centre is,

(a) zero 

(b) 10 volt

(c) The same as on 5 cm distance

(d) none 

Answer (b) 10 volt

15. The amount of energy needed in changing a condenser of capacitance 5 μF to 20 kV is

(a) 1 kJ 

(b) 10 kJ

(c) 100 kJ

(d) 5 kJ 

Answer (a) 1 kJ 

16. If the distance between two charged particles be increased, their potential energy

(a) increases 

(b) decreases

(c) remains unchanged

(d) can either increase or decrease 

Answer (d) can either increase or decrease 

17. The capacity of a conductor is inversely proportional to 

(a) area of plates

(b) permittivity of medium between plates

(c) distance between plates

(d) None of these 

Answer (b) permittivity of medium between plates

18. The unit of electric potential is volt and is equal to 

(a) joule/coulomb

(b) joule x coulomb

(c) coulomb / joule

(d) None of these

Answer (a) joule/coulomb

19. Equal charges are given to two spheres of different radii. The potential will: 

(a) be more on the smaller sphere

(b) be more on bigger sphere

(c) be equal on both the sphere

(d) depend on the nature of the materials of the spheres 

Answer (a) be more on the smaller sphere

20. The work done by electric field on a charge taken from one point to another of an equipotential surface will be

(a) positive 

(b) negative

(c) zero 

(d) any of these

Answer (c) zero 

21. If a 10 μF capacitor be charged to 5V, the charge on the capacitor is,

(a) 50 C 

(b) 50 x 10^–6 C

(c) 5 x 10^–6 C

(d) 2 C 

Answer (c) 5 x 10^–6 C

22. Each of four capacitors has a capacitance of 2 μF. To get an equivalent capacitance of 8 μF, these must be combined

(a) in series 

(b) in parallel

(c) some in series and some in parallel

(d) None of these 

Answer (b) in parallel

23. If an earthed conductor is brought near an insulated conductor, then the capacity of insulated conductor

(a) decreases 

(b) increases

(c) remain unchanged

(d) none 

Answer (b) increases

24. If a conductor is placed in an electric field, the electric field inside the conductor

(a) decreases

(b) increases 

(c) becomes zero

(d) remains unchanged

Answer (c) becomes zero