Wavelength of a light emitted from second orbit to first orbit in a hydrogen atom is

Options

A. `1.215 xx 10^(-7)` m
B. `1.215 xx 10^(-5)`m
C. `1.215 xx 10^(-4)` m
D. `1.215 xx 10^(-3)` m

Answer

A

Explanation

`1/(lambda) = R [(1)/(1^(2)) - (1)/(2^(2))] = (3R)/(4)`
`lambda = (4)/(3R) = (4)/(3 xx 1.097 xx 10^(7)) = 1.215 xx 10^(-7)`m