Question

The first line in the Lyman series has wavelength λ. The wavelength of the first line in Balmer series is.

• A. $\frac{2}{9}\lambda$
• B. $\frac{9}{2}\lambda$
• C. $\frac{5}{27}\lambda$
• D. $\frac{27}{5}\lambda$

Answer 1

Answer: (D)

$\frac{27}{5}\lambda$

Answer 2

For first line in Lyman series $\lambda_{L_{1}} = \frac{4}{3\mspace{6mu} R}$ ..... (i)

For first line in Balmer series $\lambda_{B_{1}} = \frac{36}{5\mspace{6mu} R}$ ..... (ii)

From equation (i) and (ii)

$\frac{\lambda_{B_{1}}}{\lambda_{L_{1}}} = \frac{27}{5} \Rightarrow \lambda_{B_{1}} = \frac{27}{5}\lambda_{L_{1}} \Rightarrow \lambda_{B_{1}} = \frac{27}{5}\lambda$