The angle of dip is 90o at
earth's magnetic poles
equator
both (a ) and ( b )
centere of earth
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
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
According to Curie’s law, the magnetic susceptibility of a paramagnetic substance at an absolute temperature T is proportional to :
T2
1/T
T
A bar magnet of magnetic moment is placed in a magnetic field of induction . The torque exerted on it is :
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
Above curie temperature
a ferromagnetic substance becomes paramagnetic
a paramagnetic substance becomes diamagnetic
a diamagnetic substance becomes paramagnetic
a paramagnetic substance becomes ferromagnetic
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
In frequency modulation
The amplitude of modulated wave varies as frequency of carrier wave
The frequency of modulated wave varies as amplitude of modulating wave
The amplitude of modulated wave varies as amplitude of carrier wave
The frequency of modulated wave varies as frequency of modulating wave
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
