Question

A rectangular loop consists of 80 turns, each carrying a current 8
a. the uniform magnetic field of 40 mtis directed to the right along x-axis. the loop can turn about y-axis. ifθ=30°, a = 0.4 m, b = 0.3 m, andi = 8a, what is the magnitude of the torque exerted on the loop?

Answer 1

Magnetic moment of loop is given by the formula

$M = NiA$

$M = 80*8 *0.4*0.3$

$M = 76.8$

now magnetic field is given here

$B = 40 * 10^{-3} T$

Now the torque on the loop is given by

$T = MBsin\theta$

$T = 76.8* 40*10^{-3}*sin30$

$T = 1.536 Nm$

so above is the torque on the loop.