Consider a simple rectangular coil PQRS mounted on a spindle between the poles of a…
PHYSICS · Multi-part · CBSE · Physics · Magnetic Effects of Electric Current · Magnetic Effects of Electric Current
Problem
Consider a simple rectangular coil PQRS mounted on a spindle between the poles of a horse-shoe magnet, as used in a school laboratory motor.
(a) State Fleming’s left-hand rule.
(b) Current flows from P to Q and from S to R. Using the rule stated in part (a), explain why the two opposite sides PQ and RS experience forces in opposite directions.
(c) Describe how these two forces produce a turning moment on the coil and identify the position of the coil in which this turning moment is (i) maximum and (ii) zero. Give reasons for each case.
(d) List any three independent ways by which the turning effect on the coil can be increased without changing the poles of the magnet.