Question

A photon of wavelength $4400\stackrel{\circ }{A}$ is passing through vacuum. The effective mass and momentum of the photon are respectively

• A. $5\times {10}^{-36}kg,1.5\times {10}^{-27}kg-m/s$
• B. $5\times {10}^{-35}kg,1.5\times {10}^{-26}kg-m/s$
• C. $Zero,1.5\times {10}^{-26}kg-m/s$
• D. $5\times {10}^{-36}kg,1.67\times {10}^{-43}kg-m/s$

Answer 1

The correct option is A

$5\times {10}^{-36}kg,1.5\times {10}^{-27}kg-m/s$

$p=\frac{h}{\lambda }=\frac{6.6\times {10}^{-34}}{4400\times {10}^{-10}}=1.5\times {10}^{-27}kg.m/s$
and mass $m=\frac{p}{c}=\frac{1.5\times {10}^{-27}}{3\times {10}^8}=5\times {10}^{-36}kg$