Question

A 175-turn circular loop of radius 45.0 cm is vertical, with its axis on an east-west line. A current of 200 A circulates clockwise in the loop when viewed from the east. The Earth's field here is due north, parallel to the ground, with a strength of 3.00 ✕ 10−5 T. What are the magnitude (in N · m) and direction of the torque on the loop?

Answer 1

Given : N = no of turns = 175.

r = radius of loop = 45 cm = 0.45 m

i = current in loop = 200 A

B = magnetic field = 3 x 10-5 T (towards north)

when viwed from east, the current is clockwise means area vector is towards west.

assume , east is along + x axis , north is along + y axis

upwards is + z axis.

Magnetic moment of loop = [ = area vector]

Magnetic field =

torque on current carrying loop in magnetic field is

The torque acting on the loop is 0.67 N m in the direction downward towards ground. [answer]