Question

Which statement(s) is/are correct about hydrogen spectrum?

• A. $\text{Energy of 2nd orbit is different for}{H}_1^1,H_1^{2}and{H}_1^3$
• B. $\text{Visible spectrum can be obtained in Lyman series and Balmer series}$
• C. $\text{Infrared spectrum is obtained in Paschen, Brackett and Pfund series}$
• D. $\text{Total number of emission lines obtained in Balmer series is n-2,}$$\text{where n is principal quantum number and n > 2}$

Answer 1

Answer: (C)

$\text{Infrared spectrum is obtained in Paschen, Brackett and Pfund series}$

1) Since $Z=1$ for all three isotopes, energy will be the same.

$E=13.6\frac{Z^2}{n^2}$

2) Lyman series: Ultraviolet

Balmer series: Visible

3) Paschen, Bracket, P fund $\sim$ Infrared

4) Number of spectral lines when an electron jumps from a state $n_1$ to $n_2$ is not $n-2$ but it is

$N=\frac{(n_1-2)(n_1-1)}{2}$

Hence, option $C$ is correct.