The photoelectric effect occurs only when the incident light has more than a certain minimum:

The ratio of the minimum wavelengths of the Lyman and Balmer series is ...... .

For a hydrogen atom with $n = 1$,the radius of the Bohr orbit is approximately $0.530 \, \mathring{A}$. What will be the radius for the first excited state $(n = 2)$ in $\mathring{A}$?

If the radius of an electron in the excited state of $He^{+}$ is $0.4232 \ nm$, the energy of the electron in that excited state in $J$ is: (The radius and energy of an electron in the first orbit of a hydrogen atom are $52.9 \ pm$ and $-2.18 \times 10^{-18} \ J$ respectively)

What is the potential energy of the electron in the $L$ shell of the hydrogen atom? (in $eV$)

The Bohr radius of a hydrogen-like species is $70.53 \text{ pm}$. The species and the stationary state $(n)$ are respectively (Given: Hydrogen atom Bohr radius is $52.9 \text{ pm}$)