Question

In which of the following cases, eddy currents will not be induced in the metal block?

$\left(P\right)$ A metal block is rotating about an axis of rotation, which is parallel to the direction of a uniform magnetic field.

$\left(Q\right)$ A metal block is stationary in a rapidly changing magnetic field.

$\left(R\right)$ A metal block is rotating about an axis of rotation, which is perpendicular to the direction of a uniform magnetic field.

• A. $P$
• B. $Q$
• C. $R$
• D. None of these

Answer 1

The correct option is A $P$

Eddy currents are induced in a metal block when it is either, placed in a non-uniform magnetic field or, is rotating about an axis of rotation which is perpendicular to the direction of the uniform magnetic field.

If the axis of rotation is parallel to the direction of the uniform magnetic field, eddy currents are not induced as emf is not induced.

Hence, option $\left(A\right)$ is the correct answer.