Question

Graph between maximum kinetic energy of electron and frequency of incident photon in photoelectric effect is shown. The slope of the curve is

• A. Charge of an electron
• B. Work function of metal
• C. Planck’s constant
• D. Ratio of Planck’s constant and charge of electron

Answer 1

The correct option is C Planck’s constant

For incident photon of frequency $\nu$, the K.E of the ejected electron, $E_k$ is given by
$h\nu =\varphi +E_k$
where $\varphi$ is a constant and a property of the material.

$\therefore E_k=h\nu -\varphi$
This is of the form $y=mx+c$ (eqn. of a straight line).


Slope of the line $=h=$ Planck's constant