CUET · PHYSICS · PYQ PAPER 2025
The figure shows the energy level diagram of the hydrogen atom. Out of the six given transitions, which transition results in the emission of a photon of wavelength 4870 \( \text{\AA} \)? : (\( h = 6.63 \times 10^{-34} \text{ Js} \))

- A n = 4 to n = 2
- B n = 3 to n = 1
- C n = 4 to n = 1
- D n = 3 to n = 2
Answer & Solution
Correct Answer
(A) n = 4 to n = 2
Step-by-step Solution
Detailed explanation
\(E = \frac{hc}{\lambda e}\) \(E = \frac{(6.63 \times 10^{-34} \text{ Js}) \times (3 \times 10^8 \text{ m/s})}{(4870 \times 10^{-10} \text{ m}) \times (1.602 \times 10^{-19} \text{ J/eV})}\) \(E \approx 2.55 \, \text{eV}\)…
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