Question

An X-ray photon has a wavelength $0.01\mathring{A}$. Its momentum (in $kgm{s}^{-1}$ ) is :

• A. $6.66\times 10^{-22}$
• B. $3.3\times 10^{-32}$
• C. $6.6\times 10^{-22}$
• D. $0$

Answer 1

Answer: (C)

From the relation of momentum and wave length $p=\frac{h}{\lambda }$
(Here: $\lambda =0.001\mathring{A},h=6.6\times 10^{-34}{J}_s$ )
$p=\frac{6.6\times 10^{-34}}{0.01\times 10^{-10}}=6.6\times 10^{-22}kgm/s$