Question

Induction furnace makes use of:

Answer 1

Faraday's Law of Electromagnetic Induction

1. Induced emf in a circuit is proportional to the rate of change of magnetic flux linked with the circuit.
2. The direction of induced emf is such that it tries to oppose the cause of its generation, i.e., the variation of magnetic flux producing it.

Eddy Currents

1. Whenever a conducting body moved in a magnetic field or is placed in a varying magnetic field currents are induced in the volume of the conductor.
2. Closed circuital paths for such currents are formed in the interior of the conductor.
3. The direction of circulation of these currents is governed by Lenz's law.
4. These currents are called eddy currents.
5. These currents are often undesirable in electromagnetic machinery because they heat up the conducting materials through Joule losses.
6. The effects of eddy currents can be minimized by using laminated conductors instead of a single large body.
7. The use of thin sheets of lamina insulated from each other increases the resistance to the flow of eddy current and consequently the effects of eddy current is minimized.
8. Transformer cores are usually laminated to reduce the effects of eddy currents.
9. Though eddy currents are undesirable in many electromagnetic devices, they can also be used to our advantage in some devices.

Induction Furnace

1. The heating effect of eddy current is used in an induction furnace, where a substance is heated by placing it in a rapidly changing magnetic field.
2. A high-frequency magnetic field can be used in melting metals or extracting metals from ore.
3. Food can be uniformly cooked by placing it in a region of intense alternating magnetic fields.