Question

Assertion :When a light wave of appropriate intensity ( but any frequency) strikes a metal surface, electrons are ejected from the surface. Reason: The intensity of light wave is directly proportional to the square of its amplitude.

• 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. Assertion is incorrect but Reason is correct

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

Acc. to chemical wave theory light of higher intensity is used the $K.E$ of an ejected electron can be increased This is because greater the intensity larger the energy of light wave striking the metal surface so electrons are ejected with greater $K.E$

The energy of wave is proportional to square of its amplitude Therefore the intensity of a wave is also proportional to square of its amplitude

Acc. to me in the given question assertion and reason are correct So the answer should be Option $A$