(a) A 400mm length of conductor carrying a current of 25A is situated at right-angles to a magnetic field among two poles of an electric motor.
The poles have a circular cross-section. If the force exerted on the conductor is 80N and the total flux among the pole faces is 1.27mWb, verify the diameter of a pole face.
(b) If the conductor in part (a) is vertical, the current ?owing downwards and the direction of the magnetic field are from left to right, what is the direction of the 80N force?