Question

For light beam of wavelength $632.8\, nm$, what is the momentum of each photon in the beam?

• A. $1.05 \times 10^{-27} kg\, m \,s ^{-1}$
• B. $1.25 \times 10^{-27} kg\, m\,s^{-1}$
• C. $1.35 \times 10^{-27} kg\, m \,s ^{-1}$
• D. $1.65 \times 10^{-27} kg\, m \,s ^{-1}$

Answer 1

Answer: (A)

$ p =\frac{h}{\lambda}=\frac{6.63 \times 10^{-34} Js }{632.8 \times 10^{-9} m } $
$=1.05 \times 10^{-27} \, kg \,m \,s ^{-1} $