If in a gaseous sample of one mole of hydorgen atoms, the electron in every `H` atom is present in the `5th` orbit, then how many spectral lines would appear in its emission spectrum?

Options

A. Ten
B. Five
C. Seven
D. Four

Answer

A

Explanation

In case of large number of `H` atoms, different possible transitions can be observed leading to a large number of spectral lines. of the electron in every `H` atom is falling back to the ground state from a particular excited state `(n)`, the total number of spectral lines is given by the expression
`(n(n - 1))/(2) = (5(5-1))/(2) = (20)/(2) = 10`
The brightness or intenisty of spectral lines depends upon the number of photons of same wavelength or frequency absorbed or emitted.