Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Atoms

Question:

The wavelength of the first line of Balmer series is 6563 Å. The Rydberg constant for hydrogen is about

Options:

1.09 × 107 per m

1.09 × 108 per m

1.09 × 109 per m

1.09 × 105 per m

Correct Answer:

1.09 × 107 per m

Explanation:

$\frac{1}{\lambda}=R\left[\frac{1}{4}-\frac{1}{9}\right]=\frac{5 R}{36}$

∴ R = $\frac{36}{5 \lambda}=\frac{36}{5 \times 6563 \times 10^{-10}}=1.09 \times 10^7 m^{-1}$