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 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. The value of n is given by
2
1
0. 5
0 . 25
A diamagnetic substance is brought near a strong magnet, then it is
attracted by a magnet
repelled by a magnet
repelled by north pole and attracted by south pole
attracted by north pole and repelled by south pole
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
Above curie temperature
a ferromagnetic substance becomes paramagnetic
a paramagnetic substance becomes diamagnetic
a diamagnetic substance becomes paramagnetic
a paramagnetic substance becomes ferromagnetic
A diamagnetic material in a magnetic field moves
perpendicular to the field
from weaker to the stronger parts of the field
from stronger to the weaker parts of the field
in none of the above directions
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
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
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
