Question

When the wave of hydrogen atom comes from infinity into the first orbit then the value of wave number is.

• A. 109700 cm^–1
• B. 1097cm^–1
• C. 109 cm^–1
• D. None of these

Answer 1

Answer: (A)

109700 cm^–1

Answer 2

Wave number $\bar{\nu} = \frac{1}{\lambda} = R\left\lbrack \frac{1}{n_{1}^{2}} - \frac{1}{n_{2}^{2}} \right\rbrack;n_{2} = \infty$ and $n_{1} = 1$

$\Rightarrow \bar{\nu} = R = 1.097 \times 10^{7}m^{- 1} = 109700\mspace{6mu} cm^{- 1}$