JEE Mains · Physics · STD 12 - Dual nature of radiation and matter
- JEE Mains 2024
- Hard
- Numerical
In Franck-Hertz experiment, the first dip in the current-voltage graph for hydrogen is observed at \(10.2 \mathrm{~V}\). The wavelength of light emitted by hydrogen atom when excited to the first excitation level is _______ \(\mathrm{nm}\). \(\left(\right.\) Given \(\mathrm{hc}=1245 \mathrm{eV} \mathrm{nm}, \mathrm{e}=1.6 \times 10^{-19} \mathrm{C}\) ).
Pick an option to check your answer.
Answer & Solution
Correct Answer
(A) \(122\)
Step-by-step Solution
Detailed explanation
\(10.2 \mathrm{eV}=\frac{\mathrm{hc}}{\lambda}\)
\(\lambda=\frac{1245 \mathrm{eV}-\mathrm{nm}}{10.2 \mathrm{eV}}=122.06 \mathrm{~nm}\)
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