Question

A metal surface of work function $1.07 \, eV$ is irradiated with light of wavelength $332 \, nm$ . The retarding potential required to stop the escape of photoelectrons is

• A. $1.07eV$
• B. $2.66eV$
• C. $3.7 \, eV$
• D. $4.81eV$

Answer 1

Answer: (B)

Retarding potential,
$V_{s}=\frac{h c}{\lambda e}-\frac{\phi_{0}}{e}=\frac{1240 \times 10^{- 9}}{330 \times 10^{- 9}}-1.07$
$=3.73-1.07=2.66 \, V$