The energy (in $J$) released when an excited electron of the $5^{th}$ orbit of a hydrogen atom returns to its ground state is

The radius of the $2^{nd}$ orbit of $Li^{2+}$ is $x$. The expected radius of the $3^{rd}$ orbit of $Be^{3+}$ is:

As an electron moves away from the nucleus,its potential energy

If $m$ and $e$ are the mass and charge of the revolving electron in the orbit of radius $r$ for a hydrogen atom,the total energy of the revolving electron will be:

The values of Planck's constant and the speed of light are $6.63 \times 10^{-34} \ J \ s$ and $3.0 \times 10^8 \ m \ s^{-1}$ respectively. Find the approximate wavelength in nanometers $(nm)$ of a light ray with a frequency of $8 \times 10^{15} \ s^{-1}$.

Match the spectral series of the hydrogen atom given in List-$I$ with their corresponding transitions given in List-$II$.

List-$I$	List-$II$
$(1)$ Lyman	$(A)$ $n = 2 \to n = 1$
$(2)$ Balmer	$(B)$ $n = 3 \to n = 2$
$(3)$ Paschen	$(C)$ $n = 4 \to n = 3$
$(4)$ Brackett	$(D)$ $n = 5 \to n = 4$