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
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
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
In which type of material the magnetic susceptibility does not depend on temperature?
diamagnetic
paramagnetic
ferromagnetic
ferrite
The angle of dip is 90o at
earth's magnetic poles
equator
both (a ) and ( b )
None of these
According to Curie’s law, the magnetic susceptibility of a paramagnetic substance at an absolute temperature T is proportional to
T2
1/T
T
Due to the earth’s magnetic field, charged cosmic ray particles
can never reach the poles
can never reach the equator
require less kinetic energy to reach the equator than the poles
require greater kinetic energy to reach the equator, than the poles
The work done in turning a magnet of magnetic moment M by an angle of 90o from the meridian, is n times the corresponding work done to turn it through an angle of 60o. What is the value of n ?
2
1
0. 5
0 . 25
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 antiparallel position relative to the field direction is
zero
0.5 J
2.0 J
1 J
