Electrostatic Potential and Capacitance Mock Test – Class 12 Physics

1. For two points and , the potential difference is best interpreted as:

2. A capacitor has charge on one plate and potential difference between its plates. The quantity represents:

3. In using for charges in an external field, the potential should be:

4. During movement from to , a charge goes from to . The work done by the electrostatic field is:

5. A disconnected capacitor has potential difference . A dielectric of constant is fully inserted between its plates. The new potential difference is:

6. Read the situation below and answer the question.

What field does the test charge experience inside the cavity?

7. Four charges are placed at the four corners of a square. The potential at the centre of the square is:

8. In the definition of electrostatic potential, the test charge is specified as a positive test charge mainly so that:

9. The capacitance of an isolated spherical conductor of radius in vacuum is:

10. A reducible capacitor network is connected across . One branch contains a single capacitor. The other branch contains two capacitors in series. The total charge drawn from the battery is:

11. The action of sharp points in a Van de Graaff generator is useful because:

12. A graph is described as follows.

What physical conclusion follows from this reference-level change?

13. A student’s claim says: “If the potential at a point is zero, the electric field at that point must also be zero.” The best response is:

14. The definition of electrostatic potential at a point would become physically unreliable if the test charge used were large because:

15. A compact data record for a capacitor gives , , and then states that and . The charge and energy entries are:

16. A capacitor is charged to and then disconnected. It is then connected in parallel to an identical uncharged capacitor. The final common potential difference is:

17. The torque on a dipole in a uniform electric field has magnitude:

18. Two capacitors and are connected in series across a source. The charge on each capacitor is:

19. The SI unit of capacitance follows from . It is:

20. Two charges and are separated by . Taking , their potential energy is:

21. Capacitors connected in series have the same:

22. Starting from for a positive point charge, the radial electric field magnitude is obtained as:

23. Assertion: For an isolated charged capacitor, inserting a dielectric fully reduces the stored energy.
Reason: In the isolated case, remains constant while increases.

24. A charge is displaced through a distance in a direction perpendicular to a uniform electric field . The potential difference between the initial and final points is:

25. In a diagram, equipotential surfaces are labelled , , and in order from left to right. The field lines should point:

26. A Van de Graaff generator is mainly used to:

27. Three statements about a Van de Graaff generator are given.
I. Charge delivered to the dome resides on its outer surface.
II. The dome potential rises as more charge is accumulated.
III. The belt must be a good metal conductor for charge transport.

28. In a uniform electric field directed along , point is at a distance to the right of point . The potential difference is:

29. Assertion: Inserting a dielectric fully between the plates of a parallel-plate capacitor increases its capacitance.
Reason: The dielectric reduces the effective field for the same free charge, so a smaller potential difference is produced for that charge.

30. A flat part of a -versus- graph means:

31. For a negative point charge, potentials are measured at distances and . If the potential at is , the potential at is:

32. Several capacitors are connected in parallel. The equivalent capacitance is:

33. A capacitor is charged by a source from to final charge . The -versus- graph is a straight line through the origin. If the final values are and , the stored energy is:

34. For two unlike point charges separated by , the potential energy is negative because:

35. Match each quantity with its basic physical idea.

36. A table describes two capacitors in a parallel combination connected to a source.

The charges and are:

37. Assertion: The potential energy of two unlike charges is negative when zero energy is taken at infinity.
Reason: Work is released by the electrostatic attraction when the charges come from infinity to a finite separation.

38. For a potential , where is in and is in , the electric field component is:

39. For the same observation point, Case 1 has source charge at distance . Case 2 has source charge at distance . The ratio is:

40. The derivation of isolated spherical conductor capacitance starts with . Using , the correct result is:

41. A negative charge moves from a point at to a point at . For this motion, the signs of and are:

42. If the electrostatic field does positive work on a charge moving between two points, the change in its potential energy is:

43. A metal sphere is charged and then left undisturbed. The potential at any two points on its surface is:

44. An ideal isolated parallel-plate capacitor has charge , plate area , and vacuum between the plates. The attractive force between the plates is given by:

45. In the network of two parallel branches, Branch P has a single capacitor and Branch Q has in series with . The network is across . The total energy stored is:

46. A point has potential with infinity as the zero reference. The external work needed to bring a positive test charge slowly from infinity to is:

47. A dielectric is inserted into an isolated capacitor and is pulled in by the electric field. The decrease in stored electrostatic energy mainly appears as:

48. A student calculates between two parallel equipotential planes. The field magnitude is also . This is valid because:

49. Use the arrangement described below.

The potentials at , , and are:

50. In moving from point to point , the displacement has two parts: along a uniform field of , followed by perpendicular to the field. The total potential change is: