Calculate the mass of a photon, if its wavelength is given as $0.35 \mathrm{~nm}$.

Calculate the mass of a photon, if its wavelength is given as $0.35 \mathrm{~nm}$.
  1. $2.20 \times 10^{42} \mathrm{~kg}$
  2. $6.30 \times 10^{33} \mathrm{~g}$
  3. $6.30 \times 10^{33} \mathrm{~kg}$
  4. $18.92 \times 10^{25} \mathrm{~kg}$

Solution

According to de-Broglie equation, $ \begin{aligned} \lambda & =\frac{h}{m v} \text { or } m=\frac{h}{\lambda v} \\ & =\frac{6.626 \times 10^{-34} \mathrm{~kg} \mathrm{~m}^2 \mathrm{~s}^{-1}}{0.35 \times 10^{-9} \mathrm{~m} \times 3 \times 10^8 \mathrm{~ms}^{-1}}=6.30 \times 10^{-33} \mathrm{~kg} \end{aligned} $ Hence, the correct option is (3)

Asked in: AP EAMCET 2020 (22 Sep Shift 1)

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