PHYSICS · Single correct · CBSE · Physics · Magnetic Effects of Electric Current · Magnetic Effects of Electric Current
Problem
Two identical rectangular coils, A and B, are placed between the same pair of magnetic poles and connected separately to identical d.c. batteries.
• Coil A is fitted with a split-ring commutator.
• Coil B is fitted with two slip rings so that the current direction in each side of the coil remains fixed relative to the battery.
What motion is observed when both switches are closed?
(a) Both coils rotate continuously in the same direction
(b) Only coil B rotates continuously; coil A vibrates and then stops
(c) Only coil A rotates continuously; coil B oscillates about its initial position and gradually stops
(d) Coil A rotates continuously, while coil B rotates in the opposite direction