JEE MAIN - Physics (2012 - No. 4)
Hydrogen atom is excited from ground state to another state with principal quantum number equal to $$4.$$ Then the number of spectral lines in the emission spectra will be :
$$2$$
$$3$$
$$5$$
$$6$$
Uitleg
The possible number of the spectral lines is given
$$ = {{n\left( {n - 1} \right)} \over 2} = {{4\left( {4 - 1} \right)} \over 2} = 6$$
$$ = {{n\left( {n - 1} \right)} \over 2} = {{4\left( {4 - 1} \right)} \over 2} = 6$$