Question

In a photo electric emission process from a metal of work function 1.8 eV, the kinetic energy of most energetic electrons is 0.5 eV. The corresponding stopping potential is

• A. 1.8 V
• B. 1.3 V
• C. 0.5 V
• D. 2.3 V

Answer 1

The correct option is C 0.5 V

If $V_s$ is the stopping potential, then
Max K.E. = $K_{max}=e{V}_s$
$\Rightarrow 0.5eV=e{V}_s\Rightarrow V_s=0.5V$