The energy of an electron in the first Bohr orbit of the $H$ atom is $-13.6 \, eV$. The energy value of an electron in the first excited state of the $H$ atom is ............ $eV$.

The kinetic energy of an electron in the second Bohr orbit of a hydrogen atom is equal to $\frac{h^{2}}{xma_{0}^{2}}$. The value of $10x$ is ........ . ($a_{0}$ is radius of Bohr's orbit) (Nearest integer) [Given : $\pi=3.14$]

For which of the following,the radius will be the same as that of a hydrogen atom having $n = 1$?

When an electron jumps from $n = 5$ to $n = 2$ with all possible transitions,which of the following statements is correct?

The radius ratio of Bohr's first orbit of hydrogen-like species $He^{+}$,$Li^{2+}$,and $Be^{3+}$ is:

What is the maximum wavelength line in the Lyman series of $He^{+}$ ion?