Question

A graph is drawn between frequency of the incident radiation (on X- axis) and stopping potential (on Y-axis). Then the slope of the straight line indicates
(A) h.e
(B) h/e
(C) e/h
(D) e-h

Answer 1

Hint: -
the graph is drawn between the frequency and the stopping potential. The frequency corresponds to the frequency of incident radiation and the stopping potential corresponds to the material on which the radiation is incident. This is related to the photoelectric effect.

Complete step by step solution:
From photoelectric effect, Einstein equation is given by $h\nu =h{{\nu }_{0}}+KE$
Here $h\nu$ in the energy of the incident radiation and $h{{\nu }_{0}}$is the work function of the metal. If the work function is more than the energy of the incident radiation then no photo electrons will be emitted.

In terms of stopping potential kinetic energy can be written as $e{{V}_{0}}$, so our equation becomes $h\nu =h{{\nu }_{0}}+e{{V}_{0}}$

$$eV=h\nu -h{{\nu }_{0}} \\\ V=\frac{h(v-{{v}_{0}})}{e} \\\$$

Or it can be written as $V=\frac{h}{e}v-h{{\nu }_{0}}$
On y axis was stopping potential and on x axis is frequency, compared with the equation of straight line the slope comes out to be $\frac{h}{e}$.

So, the correct option is (B)

Additional Information:
Photoelectric effect is the phenomenon of emission of electrons when radiation of a given frequency is incident on the metal. There exists a frequency called threshold frequency below which no photo electric effect can take place. Threshold frequency changes with the change in the material.

Note:
We have written the photoelectric effect and then rechanged it by comparing it to the equation of straight line. We know the equation of the straight line is given by y=mx+C where C is the intercept on y axis and if the line passes through origin then the value of C is zero.