Question

Light of Balmer series of $H{e}^{+}$ is able to eject photo electrons from a metal. What can be the maximum work function of metal?

• A. 10.2 eV
• B. 3.4 eV
• C. 13.6 eV
• D. 5.3 eV

Answer 1

The correct option is C 13.6 eV


$E_{max}=E_{{\infty }^{-}}-E_L$
$=0-\left\{\frac{-13.6}{\text{/}4}\right\}\times \text{/}4=13.6eV$
for emission
$\frac{hc}{\lambda }>\varphi 13.6>\varphi {\varphi }_{max}=13.6eV$