Hydrogen atom in ground state is excited by a monochrmatic radiation of λ=975 Å. Number of spectral lines in the resulting spectrum emitted will be

Options

(a) 3
(b) 2
(c) 6
(d) 10

Correct Answer:

6

Explanation:

For the λ=975 Å
1 / λ = R [(1/n₁²) – (1/n₂²)]
where R is the Rydberg constant
Solving we get n₂ = n = 4 (Since, n₁ = 1 ground state)
Therefore number of spectral lines = n(n – 1) / 2 = 4(4 – 1) / 2 = 6.