The shortest wavelength in the Balmer series of hydrogen atom would be (Given $R= 1.1 × 10^7 m^{-1}$) |
3636 Å 4529 Å 2433 Å 3454 Å |
3636 Å |
The correct answer is Option (1) → 3636 Å Explanation: For the hydrogen atom, wavelength in any spectral series is given by the Rydberg formula: $ \frac{1}{\lambda} = R_H \left( \frac{1}{n_1^2} - \frac{1}{n_2^2} \right) $ where $ R_H = 1.097 \times 10^7\ \text{m}^{-1} $. For the Balmer series, $ n_1 = 2 $ and $ n_2 = 3, 4, 5, \dots $ The shortest wavelength corresponds to the largest energy difference, i.e., when $ n_2 \to \infty $. Hence, $ \frac{1}{\lambda_{min}} = R_H \left( \frac{1}{2^2} - \frac{1}{\infty^2} \right) = R_H \left( \frac{1}{4} \right) $ $ \lambda_{min} = \frac{4}{R_H} = \frac{4}{1.097 \times 10^7} = 3.64 \times 10^{-7}\ \text{m} $ $ \lambda_{min} = 364\ \text{nm} = 3640\ \text{Å} $ Therefore, the shortest wavelength in the Balmer series is $ 3640\ \text{Å} $. |