Question

Energy of a photon having wave number $1.00c{m}^{-1}$ is

• A. $6.62\times {10}^{-34}$ J
• B. $1.99\times {10}^{-23}$ J
• C. $6.62\times {10}^{-32}$ J
• D. $6.62\times {10}^{-36}$ J

Answer 1

The correct option is B $1.99\times {10}^{-23}$ J

As energy of a photon,

$E=ht=h_c$

Here, $h=6.626\times {10}^{-34\lambda }Js$

As wavelength $\left(\lambda \right)=1{cm}^{-1}=0.01/m$

Speed of light, $c=3\times {10}^{8}m/s$

So, Energy $=\frac{6.626\times {10}^{-34}\times 3\times {10}^8}{0.01}$

Energy of photon $=1987.8\times {10}^{-26}J$

Energy of photon $=1.99\times {10}^{-23}J$

Hence, this is the answer.