Of the following fig.,the lines of magnetic induction due to a magnet SN, are given by

Solution

As lines of magnetic induction B are continuous curves,they run continuously through the bar and outside, as shown in Fig. (1).

At a temperatur of 30°C, the susceptibility of a ferromagnetic material is found to be x. Its susceptibility at 333°C is

x
0.5x
2x
11.1x

Solution

The variation of magnetic susceptibility (x) with temperature for a diamagnetic substance is best represented by

A curve between magnetic moment and temperature of magnet is

When 2 ampere current is passed through a tangent galvanometer, it gives a deflection of 30º. For 60º deflection,the current must be

1 amp.
2√3 amp.
4 amp.
6 amp.

Solution

As \(\frac{i_{2}}{i_{2}}=\frac{tan0_{2}}{tan0_{1}}\)

A bar magnet of magnetic moment M and length L is cut into two equal parts each of length L/2. The magnetic moment of each part will be

M
M/4
√2 M
M/2

Solution

As magnetic moment = pole strength x length and length is halved without affecting pole strength,therefore, magnetic moment becomes half.

The force between two short bar magnets with magnetic moments M₁ and M₂ whose centres are r metres apart is 8 N when their axes are in same line. if the separation is in creased to 2 r, the force between them in reduced to

4 N
2 N
1 N
0.5 N

Solution

Two identical magnetic dipoles of magnetic moments 1.0 A-m² each, placed at a separation of 2 m with their axis perpendicular to each other. The resultant magnetic field at point midway between the dipole is

5 × 10^–7 T
5 × 10^–7 T
10^–7 T
2 × 10^–7 T

Solution

Two tangent galvanometers having coils of the same radius are connected in series. A current flowing in them produces deflections of 60º and 45º respectively. The ratio of the number of turns in the coils is

4/3
\(\frac{\sqrt{3}+1}{1}\)
\(\frac{\sqrt{3}+1}{\sqrt{3}-1}\)
\(\frac{\sqrt{3}}{1}\)

Solution

In series, same current flows through two tangent galvanometers.

A bar magnet 8 cms long is placed in the magnetic merdian with the N-pole pointing towards geographical north. Two netural points separated bya distance of 6 cms are obtained on the equatorial axis of the magnet. If horizontal component of earth’s field = 3.2 × 10^–5T, then pole strength of magnet is

5 ab-amp × c
10 ab-amp × cm
2.5 ab-amp × cm
20 ab-amp × cm

Solution

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