NCERT Physics Class 12 Exemplar Chapter 1 Electric Charges and Fields Part 4

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Q.9 The Electric field at a point is

  1. Always continuous.

  2. Continuous if there is no charge at that point.

  3. Discontinuous only if there is a negative charge at that point.

  4. Discontinuous if there is a charge at that point.

Answer: (B), (D)

Q.10 If there were only one type of charge in the universe, then

  1. on any surface.

  2. if the charge is outside the surface.

  3. could not be defined.

  4. if charges of magnitude were inside the surface.

Answer: (B), (D)

Q.11 Consider a region inside which there are various types of charges but the total charge is zero. At points outside the region

  1. The electric field is necessarily zero.

  2. The electric field is due to the dipole moment of the charge distribution only.

  3. The dominant electric field is for large , where r is the distance from a origin in this region.

  4. The work done to move a charged particle along a closed path, away from the region, will be zero.

Answer: (C), (D)

Q.12 Refer to the arrangement of charges in Fig. and a Gaussian surface of radius with at the centre. Then

Guassian surface

Tittle: Image of The Gaussian surface of radius R

Guassian Surface

Tittle: Image of The Gaussian surface of radius R

  1. Total flux through the surface of the sphere is .

  2. Field on the surface of the sphere is .

  3. Flux through the surface of sphere due to is zero.

  4. Field on the surface of sphere due to is same everywhere.

Answer: (A), (C)