Question

The induction furnace is based on the heating effect of

• A. Electric field
• B. Eddy current
• C. Magnetic field
• D. Gravitational field

Answer 1

The correct option is B

Eddy current

Explanation for the correct option

In the case of option B,

1. The working of the induction furnace is based on two phenomena.
2. The first one is electromagnetic induction and the second one is joule's heating.
3. Eddy currents are current loops that develop over the surfaces of conductors as a result of shifting magnetic flux.
4. They are used in electromagnetic damping, braking, levitation, and induction heating. Slotting the conductor surface and laminating can reduce them.
5. Induction furnaces use eddy current technology. A piece of metal placed in a rapidly varying magnetic field melts due to the heat produced by the Joule effect.

Explanation for the incorrect options:

In the case of option A,

1. Electric field heating is utilized for substances that are conductive electrically in nature.
2. Whereas in induction heating internal heat generation within the workpiece is used.

In the case of option C:,

1. Even in electromagnets heat is produced when current flow through them.
2. The heat produced in magnetic materials is due to hysteresis or eddy current losses.

In the case of option D,

1. The gravitational field exists around the earth and even around every particle of mass that moves with it.
2. In actuality, gravity itself cannot be employed as a source of energy at all.
3. Whereas induction heating is based on electromagnetic induction.

Hence, option B is the correct answer.