Question

In which of the following devices, the eddy current effect is not used ?

• A. electromagnet
• B. electric heater
• C. induction furnace
• D. magnetic braking in train

Answer 1

The Correct Option is B

The question asks for the identification of a device where the eddy current effect is not utilized. To answer this, let's understand what eddy currents are and in which devices they are typically used.

Eddy Currents: These are loops of electric current induced within conductors by a changing magnetic field. When a conductor experiences a changing magnetic field, the eddy currents flow in the plane perpendicular to the magnetic field and can result in energy losses due to resistive heating of the conductor.

Devices Utilizing Eddy Currents:

• Electromagnets: While electromagnets themselves don't utilize eddy currents, the magnetic fields they produce can induce eddy currents in nearby conductive materials.
• Induction Furnace: Utilizes eddy currents to heat metals. The alternating magnetic field generated induces eddy currents in the metal, increasing its temperature due to resistive heating.
• Magnetic Braking in Trains: Utilizes eddy currents for braking purposes. When a strong magnetic field is applied to the wheels or track, eddy currents are induced, opposing the motion and causing the train to slow down.

Non-Utilization of Eddy Currents:

• Electric Heater: This device primarily uses resistance heating where current flows through a resistive element converting electrical energy into heat. It does not utilize the effects of eddy currents. Instead, it relies on the basic principle of electrical resistance where the resistive element heats up as electricity passes through it.

Conclusion: Among the options provided, the electric heater does not make use of eddy currents. It functions based on resistive heating without any involvement of magnetic fields or induction which is required for eddy currents.