Question

The maximum energy $K_{max}$ of photoelectrons emitted in a photoelectric cell is measured using lights of various frequencies $v$. The given graph shows how $K_{max}$ varies with $v$. The slope of the graph is equal to

• A. the charge of an electron
• B. the charge to mass ratio of an electron
• C. the work function of the emitter in the cell
• D. Planck's constant.

Answer 1

The correct option is D Planck's constant.

We know that, $K_{max}=e{V}_0=h(v-v_0)$
This is a straight line with slope equal to $h$, i.e., the Planck's cosntant. Hence, the correct choice is (d).