Question

Monochromatic photons of energy $3.3eV$ are incident on a photo sensitive surface of work function $2.4eV$. Calculate the threshold frequency of incident radiation.

• A. $6.82\times {10}^{14}Hz$
• B. $5.82\times {10}^{14}Hz$
• C. $7.82\times {10}^{14}Hz$
• D. $10.82\times {10}^{14}Hz$

Answer 1

Answer: (B)

$5.82\times {10}^{14}Hz$

Given,
$\varphi =2.4eV$

And,
$\varphi =h{\nu }_{\odot }$ where ${\nu }_{\odot }=$ threshold frequency.

$2.4\times 1.6\times {10}^{-19}=6.6\times {10}^{-34}{\nu }_{\odot }$

${\nu }_{\odot }=\frac{38.4\times {10}^{-14}}{6.6}=5.82\times {10}^{-14}eV$

Hence option $\text{B}$ is correct.