Question

If a convex lens is kept in water its convergent power decreases. Focal length of convex lens in water increases.

• A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion
• B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
• C. Assertion is true but Reason is false
• D. Assertion is false but Reason is true

Answer 1

Answer: (A)

Both Assertion and Reason are true and Reason is the correct explanation of Assertion

Answer 2

Eddy currents are produced when a metal sheet is placed in a changing magnetic field. In the metal sheet, we can consider closed loops as shown in the figure, through which an induced current flows due to a change of magnetic flux. This current is called eddy current and it gives rise to loss of thermal energy.