First slide

Photo Electric Effect

Question

A photon of energy 4 eV is incident on a metal surface whose work function is 2 eV. The minimum reverse potential to be applied for stopping the emission of electrons is

Easy

A

6 V
B

4 V
C

2 V
D

8 V

Solution

From Einstein's photoelectric equation
$\begin{array}{l} E_{k} = \frac{1}{2} {mv}_{\max}^{2} = hv - W \\ Where E_{k} is maximum kinetic energy of electron, v is frequency and W is work function . \\ \Rightarrow \frac{1}{2} {mv}_{\max}^{2} = 4 eV - 2 eV = 2 eV \\ but \frac{1}{2} {mv}_{\max}^{2} = {eV}_{o} \\ where V_{o} is stopping potential . \\ Thus, {eV}_{o} = 2 eV \Rightarrow V_{o} = 2 V . \end{array}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App