Electrostatic Potential and Capacitance Mock Test – Class 12 Physics

1. The most suitable reason for using infinity as for an isolated charge distribution is:

2. A slow movement of charge is considered between two points in an electrostatic field. Why is the idea of work useful before introducing detailed formulas?

3. A hollow conductor has an empty cavity and is placed in a strong external electrostatic field. A claim says that the cavity field must be strong because the outside field is strong. The best evaluation is:

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

5. A charged conductor has a non-zero electric field just outside its surface. In electrostatic equilibrium, the field at the surface must be:

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

7. A neutral hollow conductor contains a charge inside its cavity. The charges induced on the inner and outer surfaces of the conductor are:

8. In a series combination of two capacitors and , the voltage ratio is:

9. After a parallel-plate capacitor is disconnected from the battery, a dielectric of constant is fully inserted between the plates. The stored energy:

10. The graph of versus for two unlike charges, with at infinity, is best described as:

11. The row that correctly gives the voltage division for series capacitors carrying the same charge is:

12. A graph is described as follows.

What physical conclusion follows from this reference-level change?

13. A summary line says that the potential due to point charges at distances from a point is . This line mainly emphasizes:

14. A point charge is at the centre of a spherical equipotential surface of radius . If a small positive test charge moves along the surface, the work done by the electrostatic field is:

15. A capacitor is charged from a battery of voltage through ordinary connecting wires. The energy supplied by the battery and the energy finally stored in the capacitor are:

16. A charge moves from to along Path I and returns from to along Path II in an electrostatic field. If the field does of work on the first part, the field work on the return part is:

17. The row that correctly describes the orientation of a dipole in a uniform electric field is:

18. A charge is moved slowly from one point to another on the same equipotential surface. The work done by the external agent is:

19. The maximum potential of a Van de Graaff dome in air is limited mainly by:

20. When a positive charge is moved from a point of lower potential to a point of higher potential, its electrostatic potential energy:

21. Two cases are described for the same parallel-plate capacitor.

The correct comparison is:

22. With a parallel-plate capacitor connected to a battery, the potential difference remains constant. If the plate separation is reduced to half, the charge on the plates:

23. A charge arrangement has three point charges at equal distance from point : , , and . The potential at is:

24. A charge is moved from one equipotential surface at to another at . For a positive charge, the electric field does positive work when the movement is:

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

26. Use the arrangement described below.

What is the potential at ?

27. The relation is completed by:

28. A dipole in a uniform electric field has , where is the angle between and . Its potential energy is:

29. Three statements are made about potential energy in electrostatics.
I. For a single charge in an external potential, .
II. For two point charges, their mutual energy is .
III. For many point charges, every distinct pair contribution is counted twice.

30. A capacitor and an capacitor are connected in series across a battery. The battery is then disconnected, and a dielectric of constant is fully inserted into the capacitor only. The new total potential difference across the series combination is:

31. A proton is accelerated from rest through a potential difference of in a Van de Graaff setup. The energy gained by the proton is:

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

33. A -versus- graph for a linear capacitor is a straight line through the origin. The slope of this graph represents:

34. A potential graph has two straight portions. From to , decreases from to . From to , remains . The field magnitudes are:

35. A uniform field is represented by equipotential planes separated by . Adjacent planes differ by . If the potentials decrease along , the electric field is:

36. A dipole initially at is allowed to rotate freely in a uniform electric field. Ignoring energy losses, it tends first to rotate toward:

37. A point lies on the perpendicular bisector of a dipole, so it is equally distant from and . The electric potential at that point is:

38. Two points lie on the same equipotential surface of potential . A charge is moved slowly from one point to the other. The change in potential energy is:

39. A capacitor remains connected to a battery while a dielectric of constant is fully inserted. If the initial stored energy is , the final energy stored in the capacitor is:

40. A charged capacitor is disconnected from the battery. Its initial field is and potential difference is . After a dielectric of constant completely fills the space between the plates, the new field and potential difference are:

41. The row that correctly compares potential and electric field due to a point charge is:

42. A data table for a capacitor is shown below.

The capacitance indicated by the data is:

43. Consider the statements about reference level in electrostatic potential.
I. Potential value at a point is always stated relative to some chosen zero level.
II. For isolated charge distributions, infinity is commonly chosen as .
III. Changing the reference level changes all electric field directions automatically.

44. A dipole of moment is placed in a uniform electric field of . At , the torque magnitude is nearest to:

45. A point is at distances , , and from charges , , and , respectively. The net potential at is, taking :

46. The far-field potential of a dipole changes sign when a point crosses the equatorial plane because:

47. The row that correctly compares torque and potential energy of a dipole in a uniform electric field is:

48. In calculating the electrostatic potential energy of a system of point charges, the term should be counted:

49. The exact expression for a dipole potential is based on:

50. For a fixed far-field direction , the distance from a dipole is doubled. The dipole potential becomes: