Question

Identify the wrong statement
A. Eddy currents are produced in a steady magnetic field.
B. Eddy currents can be minimized by using a laminated core.
C. Induction furnace uses eddy current to produce heat.
D. Eddy current can be used to produce breaking force in moving vehicles.
E. Power meters are working on the principle of eddy currents.

Answer 1

Hint: In this question we should know the concept of eddy currents. How they are produced and what are the basic applications of eddy currents. Then solve the question by options elimination method.



Complete answer:
Eddy current is defined by the induced current in a conducting body due to a change in magnetic flux. Free electrons are present in a conductor, facing a magnetic force when the conductor encounters a change in the magnetic flux. Consequently, these free electrons will move in the form of small loops or eddies due to the effect of the magnetic force on free electrons. Therefore, electric current is generated due to electronic motion. This process follows Faraday’s law of magnetic induction.

When metal is kept under a steady magnetic field, the number of magnetic field lines passing through the metal surface does not vary or unchanged, then no eddy current is induced in it.
Option (A) is not the right statement.

These currents can be minimized by using lamination metal to make the laminated core. The rearrangement of the plane of laminations must be parallel to the magnetic field for reducing the strength of the eddy current.
Hence option( B) is also correct.

Option (C) is also right as Eddy currents are used in an induction furnace to generate heat.

The electric braking system works on the principle of eddy current. These currents create heat-producing resistance that is used to provide the breaking power of vehicles.
Hence option (D) is correct.

Finally, option (E) is also right as there is a shiny metal disc in the power meter, that rotates due to eddy currents generated in the disc by magnetic fields produced by alternating current.
Thus, option (A) wrong statement .






Note:Eddy current can also have some drawbacks like eddy current brakes can not be used in low-speed vehicles or vehicles running at low speed, can only be used for electrically conducting materials, training and skills are required is more extensive than any other techniques, limited depth standard, etc.