JEE MAIN - Physics (2017 - 8th April Morning Slot - No. 9)
A magnetic dipole in a constant magnetic field has :
maximum potential energy when the torque is maximum.
zero potential energy when the torque is minimum.
zero potential energy when the torque is maximum.
minimum potential energy when the torque is maximum.
Spiegazione
In uniform magnetic field, the torque experienced by the magnetic dipole is $$\tau $$ = MB sin $$\theta $$
Torque will be maximum when $$\theta $$ = 90o
$$\tau $$max = MB sin90o = MB
Potential energy of magnetic dipole,
$$\mu $$ = $$-$$ MB cos $$\theta $$
at maximum torque,
$$\mu $$ = $$-$$ MB cos 90o = 0
Torque will be maximum when $$\theta $$ = 90o
$$\tau $$max = MB sin90o = MB
Potential energy of magnetic dipole,
$$\mu $$ = $$-$$ MB cos $$\theta $$
at maximum torque,
$$\mu $$ = $$-$$ MB cos 90o = 0