A current carrying loop is placed in a uniform magnetic field in four different orientations as shown in figure. Arrange them in the decreasing order of potential energy.

Options

A. I gt III gt II gt IV
B. I gt II gt III gt IV
C. I gt IV gt II gt III
D. III gt IV gt I gt II

Answer

C

Explanation

`U=-MB=-MBcos theta` Here M= magnetic moment of the loop `theta=` angle between M and B
U is maximum when `theta=180^(@)` and minimum when `theta=0^(@)`. So as `theta` decreases form `180^(@)` to `0^(@)` its PE also decreases.