(a) Faraday’s laws of electromagnetic induction : 

(i) Whenever the amount of magnetic flux linked with a circuit changes, an emf is induced in the circuit. The induced emf lasts so long as the change in magnetic flux continues.

(ii) The magnitude of emf induced in a circuit is directly proportional to the rate of change of magnetic flux linked with the circuit. 

(b) Lenz’s law is in accordance with the law of conservation of energy.

For example : 

When N-pole of magnet is moved towards the coil, the upper face of the coil acquires north polarity. 

Therefore,

Work has to be done against the force of repulsion, in bringing the magnet closer to the coil. 

Similarly,

When N-pole of magnet is moved away,

South polarity develops on the upper face of the coil. 

Therefore, 

Work has to be done against the force of attraction, in taking the magnet away from the coil. It is this mechanical work done in moving the magnet w.r.t. the coil that changes into electrical energy producing induced current. 

Thus, 

Energy is being transformed. 

When we do not move the magnet, 

Work done is zero. 

Therefore, 

Induced current is zero. 

Hence,

Lenz’s law obeys the principle of energy conservation. 

Conversely, 

Lenz’s law can be treated as a consequence of the principle of energy conservation.