Q. Taking Rydberg’s constant $R_{H} = 1.097 \times 10^{7}m$, first and second wavelength of Balmer series in hydrogen spectrum is
A) $2000\ \mathring{\mathrm{A}},\ 3000\mathring{\mathrm{A}}$
B) $1575\ \mathring{\mathrm{A}},\ 2960\ \mathring{\mathrm{A}}$
C) $6529\ \mathring{\mathrm{A}},\ 4280\ \mathring{\mathrm{A}}$
D) $6552\ \mathring{\mathrm{A}},\ 4863\ \mathring{\mathrm{A}}$
Explanation
(d) $\frac{1}{\lambda} = R\left\lbrack \frac{1}{n_{1}^{2}} - \frac{1}{n_{2}^{2}} \right\rbrack$. For first wavelength $n_{1} = 2,n_{2} = 3 \Rightarrow \lambda_{1} = 6563\ \mathring{\mathrm{A}}$. For second wavelength $n_{1} = 2,n_{2} = 4 \Rightarrow \lambda_{2} = 4861\ \mathring{\mathrm{A}}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.