Question

According to Einstein's photoelectric equation, the graph of K.E. of the photoelectron emitted from the metal versus the frequency of the incident radiation gives a straight line graph, whose slope

• A. is same for all metals and independent of the intensity of the incident radiation.
• B. depends on the nature of the metal.
• C. depends on the intensity of the incident radiation.
• D. depends on the nature of the metal and also on the intensity of incident radiation.

Answer 1

The correct option is A is same for all metals and independent of the intensity of the incident radiation.

Kinetic energy of photo electron emitted $K.E=h\nu -\varphi$

where $\nu$ is the frequency of incident radiation and $\varphi$ is the work function of the metal.

Thus graph of $K.E$ Vs $\nu$ is a straight line with slope equal to $h$, having an intercept on negative y-axis which is equal to the work function $\left(\varphi \right)$ of metal.

As $h$ is a constant, thus the slope is same for all metals and independent of the intensity of the incident radiation.