Question

In a hydrogen atom, the electron is in nth excited state. It comes down to the first excited state by emitting `10` different wavelength. The value of `n` is
A. 6
B. 7
C. 8
D. 9

Answer 1

Correct Answer - A
Number of possible emission lines are `n (n - 1)//2` when an electron jumps from `n^(th)` state to ground state. In this question, this value should be `(n - 1) (n - 2) //2`
Hence, `10 = (n- 1) (n - 2)/(2)`
`"Solving this, we get" `n = 6`.