Question

The first emission line in the emission spectrum of hydrogen in the Balmer series appears at

(a) 9R/400 cm^-1

(b) 7R/144 cm^-1

(c) 3R/4 cm^-1

(d) 5R/36 cm^-1

Answer 1

Correct option is (d) 5R/36 cm^-1

First line appears for jump n = 3 to n = 2 for which

\(\bar v = R \left(\frac 1{2^2} - \frac 1{3^2}\right) \)

\(= \frac {5R}{36}\)