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## Homework Statement

a coil 2 cm in diameter has 300 turns. what is the maximum torque on this coil when it carries a current of 10mA and is placed ina constant magnetic field of 0.05 Teslas?

## Homework Equations

magnetic force on a current F = IL X B where X indicates cross product, I is current, L is length of coil, B is magnetic field

torque tau = rFsin(theta) where r is radius, F is magnetic force on current

## The Attempt at a Solution

basically subbed in IL X B for F in rFsin(theta)

and since r is radius, it is two times the diameter, 2*0.02 meters

so torque tau = (2*0.02)[(10*10^-3)(300)(0.05)sin(90)]sin(90) = 0.06 N/m

and since we won't max torque, force must be applied perpendicular, thus theta = 90 degrees.

i am unsure of the length L though, the problem states diameter is 2cm and contains 300 turns, how much is 300 turns in meters?

is my approach correct, though?

cheers