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?
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?