Answer the following with reference to Lenz’s law and the conservation of energy:
(i) Explain, with reasons, why the direction of the induced current in a circuit must oppose the change in magnetic flux that produces it.
(ii) A bar magnet is allowed to oscillate through a stationary copper ring placed coaxially around its midpoint. Describe qualitatively how the amplitude of oscillation changes with time and account for the energy transformations involved.
(iii) Why would a device that allowed the induced current to aid, rather than oppose, the change in flux lead to a violation of the principle of conservation of energy?