Question

A current carrying coil is rotated about axis PQ
in anticlockwise direction by π radians, then the
work done by external agent will be (radius of
a loop is R and B-)
21R
i
B
O
(1) ia
(2) 2ia
(3) iar
(4) 3iaR​

Answer 1

Answer:

2. I. A B

Explanation:

The amount of work done in rotating the coil  from 180° from its equilibrium position will be MB x( 1- Cos 180)

Given the radius of circular coil, r = R

The number of turns, N =1

The current flowing in the coil, i = i

The magnetic fileld, B

 The magnetic moment of current carrying loop,

M = i A N

W= 2 M B

Here, A is the area of the coil= Pi R^2

2MB = 2Pi. I. Rsquare.B

Hence, the amount of work done in rotating the coil  from 180° from its equilibrium position