Magnetism

Magnetism in a material arises due to

• spin motion of electron

• orbital motion of electron

• both orbital and spin motion of electron

• nuclear magnetism

Magnetic susceptibility for diamagnets are

• large & positive

• very small & negative

• large & negative

• small & positive

Hard magnets have

• high retentivity & high Coercivity

• low retentivity & high Coercivity

• high retentivity & low Coercivity

• low retentivity & low Coercivity

For Paramagnetic materials, Magnetic susceptibility & temperature are related as

• χ α 1/T

• χ α T

• χ α T²

• χ α T³

The earth behaves as a magnet with magnetic field pointing approximately from the geographic

• (a) North to South

• (b) South to North

• (c) East to West

• (d) West to East

The strength of the earth’s magnetic field is

• (a) constant everywhere.

• (b) zero everywhere.

• (c) having very high value.

• (d) vary from place to place on the earths surface.

Which of the following independent quantities is not used to specify the earth’s magnetic field?

• (a) Magnetic declination (θ).

• (b) Magnetic dip (δ).

• (c) Horizontal component of earth’s field (B_H).

• (d) Vertical component of earth’s field (B_V).

The critical temperature above which the ferromagnetic materials lose their magnetic property is known as

• hysteresis

• curie point

• transition temperature

• standard temperature

The relative permeability of a paramagnetic substance is

• unity

• slightly more than unity

• zero

• less than unity

The Magnetic moment per unit volume of the material is called as

• Magnetic flux density

• Intensity of Magnetization

• Magnetic flux

• Magnetic induction