Question

Assertion: The electromagnetic forces (produced as a result of eddy current) can be used for levitation, creating movement, or to give a strong braking effect
Reason:
 Eddy currents can also have undesirable effects, for instance power loss in transformers
(A) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
(B) Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
(C) Assertion is correct but Reason is incorrect
(D) Both Assertion and Reason are incorrect

Answer 1

Hint: When a changing magnetic flux is applied to a conducting material the circulating eddy currents are induced in the material. Because of the low resistance in a bulk conductor eddy currents have large magnitude and heat up the conductor. Though eddy currents have undesirable effects they are used in many applications.

Complete step-by-step solution
Eddy currents are formed in a conductor whenever some current is flowing through it. They are induced by changing magnetic fields and they swirl in nature. They form little spirals in the conductor and cause undesirable heating and power loses. They cannot be completely avoided but can be minimized by using a laminated core instead of a plain sheet. Its effects like the electromagnetic force can also be utilized in many ways like levitation, creating movement and causing a braking effect in modern vehicles using regenerative braking. Some undesirable effects include heating of the conductor skin. So, we now know that assertion is correct but reason is not the correct explanation of this.

Therefore, the correct answer is option B.

Note no matter what you do, you cannot completely eliminate the eddy currents so it’s best to have them and use them in a clever way for innovative applications E.g.: for brakes, for induction furnace, speedometers etc.