Question

A photon of energy $h v$ is absorbed by a free electron of a metal having work function $\phi<\,h v$

• A. The electron is sure to come out.
• B. The electron is sure to come out with a kinetic energy $h v-\phi$
• C. Either the electron does not come out or it comes out with a kinetic energy $h v-\phi$
• D. It may come out with a kinetic energy less than $h v-\phi$

Answer 1

Answer: (D)

$K_{\max }=h v-\phi .$ As $0 < K < K_{\max } \Rightarrow K < (h v-\phi)$