Concepts Of Physics MCQ Edition [Volume 2]PhysicsPhotoelectric Effect and Wave–Particle Duality
Suppose the frequency and intensity of a light source are both doubled. Evaluate the two statements below. (A) The saturation photocurrent remains nearly unchanged. (B) The maximum kinetic energy of the photoelectrons is doubled.
Options
- ABoth A and B are incorrect.
- BBoth A and B are correct.
- CA is incorrect but B is correct.
- DA is correct but B is incorrect.
Correct answer
D. A is correct but B is incorrect.
Step-by-step solution
The intensity I of a light source is given by I = n h , where n is the number of photons incident per unit area per unit time and is the frequency of the light. When both the intensity and the frequency are doubled, the new intensity is I' = 2I and the new frequency is ' = 2 . The new number of incident photons per unit area per unit time is n' = I' h ' = 2I h(2 ) = I h = n . Since the number of incident photons remains unchanged, the number of emitted photoelectrons per unit time remains the same. Thus, the satura