JEE Mains · Physics · STD 12 - 12. atoms
When a hydrogen atom going from \(\mathrm{n}=2\) to \(\mathrm{n}=1\) emits a photon, its recoil speed is \(\frac{\mathrm{x}}{5} \mathrm{~m} / \mathrm{s}\). Where \(\mathrm{x}=\) _______. (Use : mass of hydrogen atom\(\left.=1.6 \times 10^{-27 /} \ \mathrm{kg}\right)\)
- A \(17\)
- B \(18\)
- C \(19\)
- D \(20\)
Answer & Solution
Correct Answer
(C) \(19\)
Step-by-step Solution
Detailed explanation
\( \Delta E=10.2 \mathrm{eV} \) \( \text { Recoil speed(v) }=\frac{\Delta \mathrm{E}}{\mathrm{mc}} \) \( =\frac{10.2 \mathrm{eV}}{1.6 \times 10^{-27} \times 3 \times 10^8} \) \( =\frac{10.2 \times 1.6 \times 10^{-19}}{1.6 \times 10^{-27} \times 3 \times 10^8} \)…
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