A bar magnet having a magnetic moment of 2 × 10 4 JT -1 is free to rotate in a horizontal plane. A horizontal magnetic field B = 6 × 10-4 T exists in the space. The work done in taking the magnet slowly from a direction parallel to the field to a direction 60o from the field is
0.6 J
12 J
6 J
2 J
According to Curie’s law, the magnetic susceptibility of a paramagnetic substance at an absolute temperature T is proportional to
T2
1/T
T
Two bar magnets having same geometry with magnetic moment M and 2 M, are firstly placed in such a way that their similar poles are on the same side, then its period of oscillation is T1. Now the polarity of one of the magnets is reversed the time period of oscillations becomes T2. Then
T1 < T2
T1 > T2
T1 = T2
Rate of change of torque with deflection θ is maximum for a magnet suspended freely in a uniform magnetic field of induction B when
θ = 45o
θ = 60o
θ = 0o
θ = 90o
For protecting a sensitive equipment from the external magnetic field, it should be
Placed inside an aluminium can
Placed inside an iron can
Wrapped with insulation around it when passing current through it
Surrounded with fine copper sheet
The dimensions of magnetic dipole moment will be
LA
ML-1 A
ML-1 A -2
L2 A
A bar magnet is placed with its north pole pointing earth’s north. The points of zero magnetic field will be which direction from the centre of the magnet?
North and South
East and West
North-east and South-west
North-east and South-east
If a diamagnetic substance is brought near the north or the south pole of a bar magnet, it is
Repelled by both the poles
Repelled by the north pole and attracted by the south pole
Attracted by the north pole and repelled by the south pole
Attracted by both the poles
A bar magnet has a magnetic moment of 2.5 JT-1 and is placed in a magnetic field of 0.2 parallel to anti parallel position relative to the field direction is
Zero
0.5 J
2.0 J
1 J
A bar magnet is oscillating in earth’s magnetic field with a period T. What happen to its period of motion, if its mass is quadrupled?
Motion remains simple harmonic with new period = T/2
Motion remains simple harmonic with new period = 2 T
Motion remains simple harmonic with new period = 4 T
Motion remains simple harmonic and the period stays nearly constant
