Question

A hydrogen atom in its ground state is irradiated by light of wavelength 970Å. Taking hc/e = 1.237 x ${10}^{-6}$eV m and the ground state energy of hydrogen atom as - 13.6 eV, the number number of lines present in the emission spectrum is:___

Answer 1

Wavelength = 970Å

$=\frac{12375}{970}=12.75eV$

Now we known that :

The energy gap corresponding to the given wavelength is same as for n = 4 to n = 1.
$\therefore$ Now for spectral lines = $\frac{n(n-1)}{2}$
$=\frac{4(4-1)}{2}=6Lines$