- According to Lenz’s law:-The polarity of the induced emf is such that it tends to produce induced current in such a direction that it opposes the change in magnetic flux that produced it.
- The (-) ive sign in given equatione= (-) (dΦ/dt)tells about the direction.
- According to Faraday’s law whenever there is change in the magnetic flux, emf is induced, as aresult there will be induced current.
- According to Lenz’s law the direction of the induced current will be such that it opposes the change in the magnetic flux.
- Consider a circuit where the magnetic flux is increasing, as a result flux will change and which induces the emf in the circuit, and as a result current will be induced in the circuit.
- The direction of the induced current will be such that it will oppose the cause which induced it.
- The induced current will be in such a direction that it decreases the magnetic flux.
- Note: - The induced current will try to oppose the change which is producing it.
- Consider a setup which has a coil, a magnet and a galvanometer.
- If the north pole of the magnet is brought near the coil, there will be a deflection in the galvanometer because of induced current.
- The direction of the induced current will be such that it opposes the motion of the magnet towards coil.
- Induced current will move the magnet away from the coil.
- As the north polarity of the magnet is brought near the coil as a result the induced current will be in such a direction that the face of the coil will have north polarity.
- The current will flow in the anti-clockwise direction.
- If the South Pole of the magnet was nearer to the coil then the current will flow in clockwise direction.
Lenz’s law: supports Conservation of energy
- Lenz’s law obeys conservation of energy.
- Magnet is moving as a result current is getting induced and when the magnet is not moving there is no induced current in the coil.
- There is a mechanical energy involved with the movement of the as magnet as a result mechanical energy is converted into electrical energy which is produced by the induced current.
- Magnetic energy used in moving magnet is getting transformed into electrical energy which is produced by the induced current.
- This shows that Lenz’s law supports conservation of energy where one form of energy is getting transformed into another form.
- Work done in moving the magnet is dissipated by Joule heating produced by the induced current.