Question

You have a wire of length L = 2.1 m for making a square coil of a dc motor. The current in the coil is I = 1.8 A, and the magnetic field of the motor has a magnitude of B = 0.32 T. Find the maximum torque exerted on the coil when the wire is used to make (a) a single-turn square coil and (b) a two-turn square coil.

Answer 1

A₁=(L/4)²
M₁=p₁•B=I•A₁•B=I•L²•B/16=…
A₂=(L/16)²
M₂=2p₂•B=2I•A₂•B=2I•L²•B/256=…

Answer 2

CORRECTION TO ELENA's ANSWER:

M2=2*I*L^2*B/(8^2)

Answer 3

M2 = M1/2