A circular conducting loop of negligible resistance is kept with its plane normal to a uniform magnetic field of constant magnitude. The loop is fitted with a sliding joint so that its area can be changed smoothly while the shape remains circular.
(a) Explain qualitatively why an emf is produced in the loop when its area is gradually reduced while the magnetic field remains unchanged.
(b) State the rule that decides the direction of the induced current and predict the direction of current in the loop during the reduction of its area.
(c) Describe, with proper reasoning, how the mechanical work done in reducing the loop area is converted into electrical energy dissipated in the circuit.