NCERT Physics Class 12 Exemplar Ch 5 Magnetism and Matter Part 2

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One or More than Multiple Choice Type Questions

Q.6 is the surface of a lump of magnetic material.

1. Lines of are necessarily continuous across .

2. Some lines of must be discontinuous across .

3. Lines of are necessarily continuous across .

4. Lines of cannot all be continuous across .

Answer: (A, D)

Q.7 The primary origin of magnetism lies in

1. Atomic currents.

2. Pauli Exclusion Principle.

3. Polar nature of molecules.

4. Intrinsic spin of electron.

Answer: (A, D)

Q.8 A long solenoid has turns per meter and carries a current of . It has a soft iron core of . The core is heated beyond the Curie temperature, .

1. The field in the solenoid is (nearly) unchanged but the field decreases drastically.

2. The fields in the solenoid are nearly unchanged.

3. The magnetization in the core reverses direction.

4. The magnetization in the core diminishes by a factor of about .

Answer: (A, D)

Q.9 Essential difference between electrostatic shielding by a conducting shell and magnetostatic shielding is due to

1. Electrostatic field lines can end on charges and conductors have free charges.

2. Lines of can also end but conductors cannot end them.

3. Lines of cannot end on any material and perfect shielding is not possible.

4. Shells of high permeability materials can be used to divert lines of from the interior region.

Answer: (A, C, D)

Q.10 Let the magnetic field on earth be modelled by that of a point magnetic dipole at the center of earth. The angle of dip at a point on the geographical equator

1. Is always zero.

2. Can be zero at specific points.

3. Can be positive or negative.

4. Is bounded.

Answer: (B, C, D)