The frequency and intensity of a light source are both doubled. Consider the following statements.

(A) The saturation photocurrent remains almost the same.


(B) The maximum kinetic energy of the photoelectrons is doubled.


Intensity of light is doubled and therefore the photocurrent will be doubled since. Also, at the same time, the frequency is doubled and therefore, the stopping potential increased by more than double. The increase in stopping potential decreases the photocurrent. Hence taking the above combined effect, the saturation current (photocurrent) thus remains almost same. So, the statement A is true.


The maximum kinetic energy of photoelectron is given by



Where, =Planck’s constant; =frequency of the light and =Work function of the metal


Now, if frequency is doubled, the maximum kinetic energy is



Multiplying 2 on both sides of equation (1) and comparing with equation (2), we get





Therefore, we conclude from above equation that the maximum kinetic energy will be more than double. Hence, statement B is false.

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