Question

The momentum of a photon in an X-ray beam of $10$ metre wavelength is

• A. $6.26\times {10}^{-34}$kg m/s
• B. $6.26\times {10}^{-35}$kg m/s
• C. $6.26\times {10}^{-33}$kg m/s
• D. $6.26\times {10}^{-36}$kg m/s

Answer 1

The correct option is B $6.26\times {10}^{-35}$kg m/s

Momentum of photon $p=\frac{h}{\lambda }$, where h=plank's constant$=6.26\times {10}^{-34}$ and $\lambda$= wavelength=10 m

Now putting the above values in the provided equation we get,

$p=\frac{6.26\times {10}^{-34}}{10}=6.26\times {10}^{-35}$kg m/s