Question 146 of 200
Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.
Assertion A : The photoelectric effect does not take place, if the energy of the incident radiation is less than the work function of a metal.
Reason R : Kinetic energy of the photoelectrons is zero, if the energy of the incident radiation is equal to the work function of a metal.
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Answer: (B) Both A and R are correct but R is not the correct explanation of A
Work function of a metal is defined as the minimum amount of energy needed for ejection of photoelectron. Therefore, Assertion is correct.
Incident energy may or may not be completely absorbed by the photoelectron. Therefore, kinetic energy of a photoelectron may be zero even if the incident radiation has energy greater than work function. Hence, though the reason is correct, it is not the correct explanation of Assertion.
Incident energy may or may not be completely absorbed by the photoelectron. Therefore, kinetic energy of a photoelectron may be zero even if the incident radiation has energy greater than work function. Hence, though the reason is correct, it is not the correct explanation of Assertion.