99 Percentile Qs Bank for JEE MainPhysicsAtomic Physics
A sample of atomic hydrogen gas is irradiated by a beam of ultraviolet radiation having a wavelength between 100 nm and 200 nm . Assuming that the atoms are in the ground state, the wavelength which will have low intensity in the transmitted beam is
Options
- A104 nm
- B103 nm
- C105 nm
- D100 nm
Correct answer
B. 103 nm
Step-by-step solution
The energy of a photon corresponding to λ = 100 nm is, 1 2 4 2 eV nm 1 0 0 nm = 1 2 · 4 2 eV Similarly, the corresponding to λ = 200 nm is 6 . 21 eV . The energy needed to take the atom from the ground state to the first excited state is E 2 - E 1 = 13 . 6 eV - 3 . 4 eV = 10 . 2 eV The energy needed to take the atom from the ground state to the second excited state is E 3 - E 1 = 13 . 6 eV - 1 . 5 eV = 12 . 1 eV The energy needed to take the atom from the ground state to the third excited state is E 4 - E 1 = 13 .