Magnetism and Matter

The susceptibility of a ferromagnetic substance is

• Zero

• > 1

• < 1

• >> 1

A bar magnet is allowed to fall vertically through a copper coil placed in a horizontal plane. The magnet falls with a net acceleration, is

• Zero

• = g

• < g

• > g

Which of the following properties is 'False' for a bar magnet ?

• It doesn't produce magnetic field.

• Its like poles repel and unlike poles attract.

• Its poles cannot be separated

• It points in North-South direction when suspended.

A jet plane of wing span 20 m is travelling towards west at a speed of 400 ms^-1. If the earth's total magnetic field is 4 × 10^-4 T and the dip angle is 30°, at that place, then the voltage differences developed across the ends of the wing is

• 0.8 V

• 6.4 V

• 3.2 V

• 1.6 V

A superconductor exhibits perfect

• ferromagnetism

• ferrimagnetism

• diamagnetism

• paramagnetism

A magnet is dropped down an infinitely long vertical copper tube. Then

• the magnet moves with continuously decreasing velocity and ultimately comes to rest.

• the magnet moves with continuosly increasing velocity and ultimately acquires a constant terminal velocity.

• the magnet moves with continuously increasing velocity and acceleration.

• the magnet moves with continuosly increasing velocity but constant acceleration.

The variation of the intensity of magnetisation (I) with respect to the magnetising field (H) in a diamagnetic substance is described by the graph

• OC

• OD

• OA

• OB