A bar magnet is hung by a thin cotton thread in a uniform horizontal magnetic field and is in' equilibrium state. The energy required to rotute it by `60^(circ)` is `W`. Now the torque required to keep the magnet in this new: position is `sqrt(k) W`. Find `k`.

A bar magnet is hung by a thin cotton thread in a uniform horizontal magnetic field and is in equilibrium state. The energy required to rotate it by 60^(@) is W. Now the torrue required to keep the magnet in this new position is

A bar magnet hung by a insulating thread In a uniform horizontal magnetic field and magnet is in equilibrium Initially. The torque required to keep the magnet at angle by 30° with the direction of magnetic field is t. Then the work done to rotate it by same angle from initial position is

A magnetic needle lying parallel to a magnetic field requires W units of work to turn through 60^(@) . The external torque required to maintain the magnetic needle in this position is