A uniform magnetic field of 3000 G is established along the positive z-direction. A rectangular loop of sides 10 cm and 5 cm carries a current of 12 A. What is the torque on the loop in the different cases shown in Fig. 4.28? What is the force on each case? Which case corresponds to stable equilibrium?

Explanation

use `tau = IA xx B ` and `F = Il xx B`
(a) `1.8 xx 10^(-2)` N m along - y direction
(b) same as in (a)
( c) ` 1.8 x 10^(-2) N` m along -x direction
( d) `1.8 xx 10^(-2) N` m at an angle of `240^@` with the +x direction
(e ) zero
( f) zero
Force is zero in each case. Case (e) corresponds to stable, and case (f) corresponds to unstable equilibrium.