According to Lenz’s law, the direction of the induced current (caused by induced emf) is always such as to oppose the change causing it.
where k is a positive constant. The negative sign expresses Lenz’s law. It means that the induced emf is such that, the induced current opposes the change in flux, if the circuit is closed.
Consider a bar magnet and a loop. The bar magnet experiences a repulsive force due to the current induced. Hence, some amount of work is done to move the magnet. The energy which is spent by the person in moving the magnet is dissipated by Joul's heating produced by induced current. Therefore, the law of conservation of energy is validated.
