21. The electric field in the vicinity of two oppositely charged parallel conductors is
- radial uniformly.
- in parallel lines between the two imaginary parallel planes passing through the centres of the two conductors.
- not uniform and its direction changes from point to point.
- 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.
22. The normal components of electric flux density across a dielectric-dielectric boundary
- are discontinuous
- are continuous
- depend on the magnitude of the surface charge density
- depend on electric field intensity
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?
- The force on the 3 nC charge is repulsive.
- A charge of -5 nC placed midway between Q1 and Q2, will experience no force.
- The forces on Q1, and Q2 are same in magnitude.
- The forces on Q1, and Q2 will depend on the medium in which they are placed
24. Consider the following statements in connection with boundary relations of electric field:
- In a single medium electric field is continuous
- The tangential components are the same on both sides of a boundary between two dielectrics.
- The tangential electric field at the boundary of a dielectric and a current carrying conductor with finite conductivity is zero.
- Normal component of the flux density is continuous across the charge-free boundary between two dielectrics.
Which of these statements is/are correct?
- i, ii and iii
- i only
- iii and iv only
- i, ii and iv
25. The capacitance of an insulated conducting sphere of radius R in vacuum is
26. Which one of the following is the correct statement?
Equipotential lines and field lines
- are parallel
- are anti-parallel
- are orthogonal
- bear no definite relationship
27. Consider the following statements for an electrostatic field:
- Its curl is zero.
- It is negative of gradient of scalar potential Φ.
- It is conservative
Which of these statements are correct
- i and ii
- ii and iii
- i and iii
- i, ii and iii
28. Fields are said to be circularly polarized if their magnitudes are
- Equal and they are in phase
- Equal and they differ in phase by ± 90°
- Unequal and they differ in phase by ± 90°
- Unequal and they are in phase
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?
- 450 nJ
- -900 nJ
- -450 nJ
30. Equipotential surfaces about a pair of equal and opposite linear charges exist in what form?
- Concentric spheres
- Concentric cylinders
- Non-concentric cylinders