A freely suspended magnet of moment `(0.98 Am^2)` is deflected through '60^0' by a couple. Calculate the magnitude of the couple if the earth's horizontal field is 0.4x10^(-4) T.

A dipole of magnetic moment (2.5 Am^2) is deflected through 30° from magnetic meridian. If the earth's horizontal field is (0.4x10^-4) I calculate the deflection moment.

Two rails of a railway track insulated from each other and the ground are connected to a milli voltmeter. What is the reading of millivoltmeter when the train travels at speed of 180 km/h along the track, given that the horizontal component of earth's magnetic field is 0.2*10^(-4) wb/m and the rails are separated by 1 meter.

(Attempt any nine of the following questions) There is an electric dipole on the x-y plane. Its dipole moment is 4 x 10^(-9) Cm . On . the same plane there is also a uniform electric field of magnitude 5x10^4 NC^(-1) . If the axis of the dipole makes an angle 30° with the electric field, calculate the magnitude of the torque acting on the dipole and also mention the di rection of torque.

A short bar magnet of magnetic moment 0.4JT^-1 is placed in a uniform magnetic field of 0.16 T. The magnet is in stable equilibrium when the potential energy is