Chemistry

Problem

In a mixture of

\text{H-He}^+

gas (

\text{He}^+

is singly ionized He atom), H atoms and

\text{He}^+

ions are excited to their respective first excited states. Subsequently, H atoms transfer their total excitation energy to

\text{He}^+

ions (by collisions). Assume that the Bohr model of atom is exactly valid. The wavelength of light emitted in the visible region by

\text{He}^+

ions after collisions with H atoms is – a.

6.5 \times 10^{-7} \text{ m}

5.6 \times 10^{-7} \text{ m}

4.8 \times 10^{-7} \text{ m}

4.0 \times 10^{-7} \text{ m}