The dynamic mass (in kg) of the photon with a wavelength corresponding to the series limit of the Ba — Atomic Structure Chemistry Question

💡 Solution & Explanation

Series limit of Balmer for He$^+$ is $n=2 \to \infty$. Energy $E = 13.6 \times \frac{2^2}{2^2} = 13.6$ eV. Dynamic mass $m = \frac{E}{c^2} = \frac{13.6 \times 1.6 \times 10^{-19}}{(3 \times 10^8)^2} = \frac{21.76 \times 10^{-19}}{9 \times 10^{16}} \approx 2.42 \times 10^{-35}$ kg. Therefore, correct answer is C.