Question

The wavelength of Lyman series for first line is :

• A. $\frac{4\times 1.097\times {10}^7}{3}m$
• B. $\frac{3}{4\times 1.097\times {10}^7}m$
• C. $\frac{4}{3\times 1.097\times {10}^7}m$
• D. $\frac{3}{4}\times 1.097\times {10}^{7}m$

Answer 1

The correct option is C $\frac{4}{3\times 1.097\times {10}^7}m$

Wavelength: $\frac{1}{\lambda }=R(\frac{1}{n_1^2}-\frac{1}{n_2^2})$

For first line of Lyman series, $n_1=1$ and $n_2=2$

$\frac{1}{{\lambda }_1}=1.097\times {10}^7(\frac{1}{1^2}-\frac{1}{2^2})$ $m^{-1}$

$⟹$ ${\lambda }_1=\frac{4}{3\times 1.097\times {10}^7}$ $m$