Question

Given below are two statements: one is labelled as Assertion (A) and the other one is labelled as Reason (R). 
Assertion (A): Emission of electrons in the photoelectric effect can be suppressed by applying a sufficiently negative electron potential to the photoemissive substance.
Reason (R): A negative electric potential, which stops the emission of electrons from the surface of a photoemissive substance, varies linearly with the frequency of incident radiation.
In light of the above statements, choose the most appropriate answer from the options given below:

• A. Both (A) and (R) are true but (R) is not the correct explanation of (A)
• B. (A) is true but (R) is false
• C. Both (A) and (R) are true and (R) is the correct explanation of (A)
• D. (A) is false but (R) is true

Hint:

In photoelectric effect, the stopping potential depends on the energy of incident photons, which in turn depends on the frequency of the radiation, but the relationship is not necessarily linear.

Answer 1

The Correct Option is A

- Assertion (A): The assertion is true. A sufficiently negative potential can stop the emission of photoelectrons. - Reason (R): The reason is also true, but it is not the correct explanation for the assertion. The stopping potential is related to the energy of the incident photons, but it does not vary linearly with frequency in the way described. 
Thus, both statements are true, but (R) does not explain (A).