A constant current `I` is flowing through a circular coil placed in uniform magnetic field `vecB` as shown. Then:

Options

A. The loop is in stable equilibrium
B. The loop is in unstable equilibrium
C. The torque acting on the loop is maximum
D. The torque acting on the loop is `(1)/(sqrt(2))` times the maximum torque

Answer

C

Explanation

Torque acting on the loop is `tau=MxxB=Mbsintheta`
Where `theta=` angle between `M` and `B`
In the figure shown `theta=90^(@)` because `B` is in place of loop.
Or `tau=MB=`maximum torque
Hence, (c) is correct and choice (d) is wrong.
Since, torque is acting on the loop so loop is not in equilibrium.
Hence, choices (a) and (b) are wrong.