Bohr’s atomic theory gave the idea of :

The frequency of radiation emitted when the electron falls from $n = 4$ to $n = 1$ in a hydrogen atom will be (Given $h = 6.625 \times 10^{-34} \, J s$):-

The energy of an electron in the first orbit of $He^+$ is $-871.6 \times 10^{-20} \ J$. The energy of an electron in the first orbit of hydrogen is ...... .

The ground state energy of $H$ is equal to

What are the $Zeeman$ and $Stark$ effects? What is their significance?

The difference in radii between the fourth and third Bohr orbits of $He^{+}$ (in $m$) is: