Question

The maximum kinetic energy of photoelectrons coming out of a metal surface is $10\, eV$. The minimum voltage required to stop, the emission of electrons from this metal surface is

• A. 10 V
• B. 5 V
• C. -5 V
• D. -10 V

Answer 1

Answer: (D)

The minimum negative potential $V_{0}$ is called stopping potential.
Here, $K_{\max }=10\, eV$
So, the stopping potential, $e V_{0}=K_{\max }$
$\Rightarrow eV _{0}=10\, eV$
Or $V_{0}=-10\, V$