The figure shows a bar magnet and a metallic coil. Consider four situations: (I) Moving the magnet away from the coil. (II) Moving the coil towards the magnet. (III) Rotating the coil about the vertical diameter. (IV) Rotating the coil about its axis. An emf in the coil will be generated for the following situations.

Question

The figure shows a bar magnet and a metallic coil. Consider four situations: (I) Moving the magnet away from the coil. (II) Moving the coil towards the magnet. (III) Rotating the coil about the vertical diameter. (IV) Rotating the coil about its axis. <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/d28f7d72d7ed978a362d58a4c8dd0928-.png" /> An emf in the coil will be generated for the following situations. (A) I and II only (B) I, II and IV only (C) I, II, and III only (D) I, II, III, and IV

Tardigrade Admin · Accepted Answer

An emf is induced in the coil when there is a flux change in the coil or when field lines are cut by the coil. When coil rotates about its axis, there is no change in flux as no field line is cut by the coil. <img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/f71aa1d9a79fab9f66153dc5d19db1ec-.png" /> So, no emf is generated in coil when it is rotated about its axis. In all other cases an emf is induced in the coil.