Question

$\text{Calculate the mass of a photon with wavelength}3.6A^{\circ }$.

Answer 1

Mass of Photon

$\text{Given: wavelength}\left(\lambda \right)=3.6A^{\circ }=3.6\times {10}^{-10}m$

$\text{We know, velocity of photon = velocity of light}=3\times {10}^{8}m{s}^{-1}$

According to de Broglie's equation:

$\text{wavelength}\left(\lambda \right)=\frac{h}{mv}$

$\text{Mass of photon (m)}=\frac{h}{\lambda v}=\frac{6.626\times {10}^{-34}Js}{(3.6\times {10}^{-10}m)(3\times {10}^{8}m{s}^{-1})}$

$m=6.135\times {10}^{-33}\text{kg}\{1J=1\text{kg}{m}^2{s}^{-2}\}$

Final Answer: Mass of a photon is $m=\text{6.135}\times {10}^{-33}kg$