Question 232 of 276
A rectangular loop of sides and , carrying a current of , is placed in different orientations as shown in the figure below.
(a)
(b) 
(c)
(d) 
If there is a uniform magnetic field of in the positive direction, in which orientations the loop would be in stable equilibrium and unstable equilibrium?
Show answer and solution
Answer: (D) (b) and (d), respectively.
For a magnetic dipole placed in a uniform magnetic field, the torque is given by , and potential energy is given as,
When is in the same direction as then and is minimum = as . Stable equilibrium is (b).
When the opposite direction of , then and is max =
As, Unstable equilibrium in (d)
When is in the same direction as then and is minimum = as . Stable equilibrium is (b).
When the opposite direction of , then and is max =
As, Unstable equilibrium in (d)
