Question

Find the longest wavelength present in the Balmer series of hydrogen.

Answer 1

For longest wavelength in Balmer series, transition takes place from $n=3$ to $n=2$

Longest wavelength $\frac{1}{\lambda }=1.097\times {10}^7(\frac{1}{2^2}-\frac{1}{3^2})$

Or $\frac{1}{\lambda }=1.097\times {10}^7(\frac{5}{36})$

$⟹\lambda =6.563\times {10}^{-7}=6563A^o$