A rectangular coil ABCD is placed between the poles of a horseshoe magnet such that…
PHYSICS · Multi-part · CBSE · Physics · Magnetic Effects of Electric Current · Magnetic Effects of Electric Current
Problem
A rectangular coil ABCD is placed between the poles of a horseshoe magnet such that side AB is close to the North pole and side CD is close to the South pole. When a steady current enters the coil through brush X connected to side AB and leaves through brush Y connected to side CD, the coil starts rotating about its central axis.
(i) Identify which arm of the coil (AB or CD) will move upwards and which will move downwards during the first half-turn. Give reason for your answer.
(ii) Explain why the coil continues to rotate in the same direction even after it has completed a half-turn.
(iii) State what would happen to the rotation if the magnetic field strength were increased while keeping the current constant. Justify your answer in qualitative terms.