A circular coil of 20 turns each of radius 10 cm and carrying a current of 5 A is placed in a uniform magnetic field of induction 0.10 T normal to the plane of the coil?

Options

A. 15 N-m
B. `3.14` N
C. Zero
D. `12.56` N

Answer

C

Explanation

`tau =nIAB sin theta` where` theta` is the angle made by the axis of the loop with the magnetic field.
As B is perpendicular to the plane of the coil, `theta =0^(@).`
`therefore tau =nIAB sin 0^(@) =0`