Question

Q.42. If radiations ranging from ultraviolet to infrared are passed through hydrogen gas at room temperature, then the absorption lines will be observed in the
(1) Lyman series
(2) Balmer series
(3) Paschen series
(4) All of these

Answer 1

(1) Lyman series

At room temperature, nearly all the atoms in hydrogen gas will be in the ground state. When light passes through the gas, photons are absorbed, causing electrons to make transitions to higher states and creating absorption lines. These lines correspond to the Lyman series since that is the series of transitions involving the ground state or n = 1 level. Since there are virtually no atoms in higher energy states, photons corresponding to transitions from n > 2 to higher states will not be absorbed.

hope this helps

hey don't forget to hit this answer as the brainliest........

Answer 2

If radiations ranging from ultraviolet to infrared are passed through hydrogen gas at room temperature, then the absorption lines will be observed in the Lyman series. Therefore, the correct option is (1) Lyman series

Explanation:

• In a Hydrogen atom, there is only one electron in the K-shell.
• This is the ground state of the hydrogen atom.
• When energy is provided, excitation of this electron can take place to a higher energy level.
• The value of the energy level in which the electron is present is $n=1$.
• Therefore, on the absorption of energy, transitions can take place from $n=1$ to $\[n = 2,\,3,\,4,\,...\infty \]$.
• As the electron is present only at the energy level having $n=1$, transitions cannot take place from other energy levels.
• The transition that takes place from $n=1$ to higher energy levels is observed in the Lyman series.
• Absorption lines in any other series will not be observed in the case of the hydrogen atom.
• Therefore, the absorption lines will be observed in the Lyman series if radiations ranging from UV to IR are passed through hydrogen gas at room temperature.

#SPJ2