If the minimum wavelength corresponding the Paschen series of hydrogen spectra is 820 nm then that corresponding to the Balmer series would be.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 364.4 nm
Wavelength of radiation emitted in hydrogen spectra
$\frac{1}{\lambda}=R\left(\frac{1}{n_1^2}-\frac{1}{n_2^2}\right)$
For Paschen $n_1=3, n_2 \geq 4$
for $\lambda_{\min} n_1=3, n_2=\infty$
$\frac{1}{\lambda_1}=\frac{R}{9}$
For Balmer $n_1=2, n_2 \geq 3$
For $\lambda_{\min } n_1=2, n=\infty$
$\frac{1}{\lambda_2}=\frac{R}{4}$
$\frac{\lambda_2}{\lambda_1}=\frac{4}{9}$
$\lambda_2=\frac{4}{9} \times \lambda_1$
$=\frac{4}{9} \times 820$
$\approx 364.4 ~nm$