Question

Two statements are given one labelled Assertion (A) and other labelled Reason (R). Select the correct answer to these questions from the options as given below.

Assertion (A): For the radiation of a frequency greater than the threshold frequency, photoelectric current is proportional to the intensity of the radiation.

Reason (R) : Greater the number of energy quanta available, greater is the number of electrons absorbing the energy quanta and greater is number of electrons coming out of the metal.

a) If both Assertion and Reason are true and Reason is correct explanation of Assertion.

b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.

c) If Assertion is true but Reason is false.

d) If both Assertion and Reason are false.

Answer 1

Option B .

For a radiation of frequency greater than the threshold frequency, the photoelectric current is proportional to the intensity of the radiation, but this does not imply that the number of energy quanta available increases the number of electrons coming out of the metal.

Step-by-step explanation:

Option B is the correct answer.

Assertion (A) states that for the radiation of a frequency greater than the threshold frequency, photoelectric current is proportional to the intensity of the radiation. This statement is true. When the frequency of the light is above the threshold frequency, the intensity of the light determines the number of photons incident on the metal surface, which in turn determines the number of electrons ejected. Higher intensity means more photons and therefore more ejected electrons.

Reason (R) states that the greater the number of energy quanta available, the greater the number of electrons absorbing the energy quanta and coming out of the metal. This statement is also true. The intensity of the radiation determines the number of photons incident on the metal surface and the energy carried by these photons. More energy quanta available means more electrons can absorb the energy and be ejected from the metal.

Therefore, both the Assertion and Reason are true, but the Reason is not the correct explanation of the Assertion. Hence, option B is the correct answer.