Question 25: Atoms & Nuclei

Question

The minimum energy required by a hydrogen atom in ground state to emit radiation in Paschen series is nearly:

Accepted Answer

To emit a PaschenÃ¢ÂÂseries photon (transition ending at $n=3$), the atom must first be excited above $n=3$. The lowest such level is $n=4$.
Energy levels of hydrogen:
$$E_n=-\frac{13.6	ext{ eV}}{n^2}$$
GroundÃ¢ÂÂstate energy $E_1=-13.6$ eV; fourthÃ¢ÂÂlevel energy
$$E_4=-\frac{13.6}{4^2}=-0.85	ext{ eV}.$$
Minimum excitation energy from $n=1$ to $n=4$:
$$\Delta E=E_4-E_1 =(-0.85)-(-13.6)=12.75	ext{ eV}.$$
Answer: Option B, 12.75 eV.

Answer

13.6 eV

Answer

12.75 eV

Answer

10.75 eV

Answer

1.5 eV

Atoms & Nuclei

The minimum energy required by a hydrogen atom in ground state to emit radiation in Paschen series is nearly:

Choose the correct answer: