Question

Calculate the wavelength of first line in the balmer series of hydrogen spectrum

Answer 1

Here we will use the following relation

(1 / λ) = 1.09677 X 107 [(1 / n1 2) - (1 / n2 2)]

For Balmer series, n1 = 2 and n2 = 3, 4, 5.....

The first line will be obtained for n2 = 3. So we will have

(1 / λ) = 1.09677 X 10^7 [(1 / 4) - ( 1 / 9)]
(1 / λ)==15233 cm-1

Solving for λ, we get
λ=6.563*10^-5cm

λ = 6.563 X 10^-7 m