Electrostatic Fields MCQ

21. The electric field in the vicinity of two oppositely charged parallel conductors is

  1. radial uniformly.
  2. in parallel lines between the two imaginary parallel planes passing through the centres of the two conductors.
  3. not uniform and its direction changes from point to point.
  4. in parallel circular paths between the two conductors, with the centre of the circles located at the mid-point of a line joining the two centres of the two conductors.

Answer. c

22. The normal components of electric flux density across a dielectric-dielectric boundary

  1. are discontinuous
  2. are continuous
  3. depend on the magnitude of the surface charge density
  4. depend on electric field intensity

Answer. c

23. Point charges of Q1 = 2 nC and Q2 = 3 nC are located at a distance apart. With regard to this situation, which one of the following statements is NOT correct?

  1. The force on the 3 nC charge is repulsive.
  2. A charge of -5 nC placed midway between Q1 and Q2, will experience no force.
  3. The forces on Q1, and Q2 are same in magnitude.
  4. The forces on Q1, and Q2 will depend on the medium in which they are placed

Answer. b

24. Consider the following statements in connection with boundary relations of electric field:

  1. In a single medium electric field is continuous
  2. The tangential components are the same on both sides of a boundary between two dielectrics.
  3. The tangential electric field at the boundary of a dielectric and a current carrying conductor with finite conductivity is zero.
  4. Normal component of the flux density is continuous across the charge-free boundary between two dielectrics.

Which of these statements is/are correct?

  1. i, ii and iii
  2. i only
  3. iii and iv only
  4. i, ii and iv

Answer. d

25. The capacitance of an insulated conducting sphere of radius R in vacuum is

  1. 2πεoR
  2. 4πεoR
  3. 4πεoR2
  4. 2πεo/R

Answer. b

26. Which one of the following is the correct statement?

Equipotential lines and field lines

  1. are parallel
  2. are anti-parallel
  3. are orthogonal
  4. bear no definite relationship

Answer. c

27. Consider the following statements for an electrostatic field:

  1. Its curl is zero.
  2. It is negative of gradient of scalar potential Φ.
  3. It is conservative

Which of these statements are correct

  1. i and ii
  2. ii and iii
  3. i and iii
  4. i, ii and iii

Answer. d

28. Fields are said to be circularly polarized if their magnitudes are

  1. Equal and they are in phase
  2. Equal and they differ in phase by ± 90°
  3. Unequal and they differ in phase by ± 90°
  4. Unequal and they are in phase

Answer. b

29. Point charges of -10 nC and 10 nC are located in free space at (-1, 0, 0) m and (1, 0, 0) m respectively. What is the energy stored in the field?

  1. 450 nJ
  2. Zero
  3. -900 nJ
  4. -450 nJ

Answer. d

30. Equipotential surfaces about a pair of equal and opposite linear charges exist in what form?

  1. Concentric spheres
  2. Concentric cylinders
  3. Non-concentric cylinders
  4. Planes

Answer. d