A square loop (L = 0.20 m)consists of 50 closely wrapped turns,each carrying a current of 0.50 A.The loop is oriented as shown in a uniform magnetic field of 0.40 T directed in the positive y direction.What is the magnitude of the torque on the loop?
A)0.21 N . m
B)0.20 N.m
C)0.35 N . m
D)0.12 N .m
E)1.73 N.m

Question

A square loop (L = 0.20 m)consists of 50 closely wrapped turns,each carrying a current of 0.50 A.The loop is oriented as shown in a uniform magnetic field of 0.40 T directed in the positive y direction.What is the magnitude of the torque on the loop? 
A)0.21 N . m 
B)0.20 N.m 
C)0.35 N . m 
D)0.12 N .m 
E)1.73 N.m

Quizplus · Accepted Answer

To find the torque on the loop, we use the equation:

τ = NIABsinθ

where N is the number of turns, I is the current, A is the area of the loop, B is the magnetic field, and θ is the angle between the normal to the loop and the magnetic field.

In this problem, we have:

N = 50 turns
I = 0.50 A
A = L^2 = (0.20 m)^2 = 0.04 m^2
B = 0.40 T
θ = 90° (since the loop is oriented perpendicular to the magnetic field)

Plugging in the values, we get:

τ = (50)(0.50 A)(0.04 m^2)(0.40 T)sin90° = 0.35 N·m

Therefore, the best choice is C, with a torque of 0.35 N·m.

A Square Loop (L = 0