Show that Lenz's law obeys the law of conservation of energy.

Explanation

Lenz.s law: See Very Short Answer Type Question No. 5 (1 Mark). Lenz.s law is the direct consequence of law of conservation of energy. Electrical energy produced in electromagnetic induction.is provided by the mechanical- energy. Explanation : Consider a solenoid connected to an electric lamp(or a sensitive galvanometer) as shown in Fig. below. Suppose that a magnet with its north pole facing the solenoid is moved towards the solenoid. The induced current is produced in the solenoid in clockwise direction, when seen from left. Due to the flow of current, the lamp glows and it radiates light energy. According to encrgy conservation prinoiple, work equivalent to the eletric encrey (which makes the lamp to glow) must be done by the agent in pushing the magnet towards the solenoid. In fact, it is exactly so. The induced current produced in the solenoid in clockwise direction (when seen from left) produces magnetic field from left towards right. When the magnet (with its north pole towards the solenoid) is moved towards the solenoid, it experiences an opposing force due to the magnetic field and hence mechanical work has to be done in moving the magnet. The work done in moving the magnet against this force results in the form of clectric energy (or induced emij in the circuit. Hence, Lenz.s law is in accordance with the law of conservation of energy.