What is the wavelength of light required to raise an electron in the $O^{7+}$ ion from $n=1$ shell to $n=2$ shell in $nm$?

The electron in a hydrogen atom is in the first Bohr orbit $(n=1)$. The ratio of transition energies,$E(n=1 \rightarrow n=3)$ to $E(n=1 \rightarrow n=2)$,is

Angular momentum of an electron in the second shell of a $Li^{+2}$ ion is:

The total number of spectral lines observed when an electron returns from the $6^{th}$ shell to the $2^{nd}$ shell in a hydrogen atom is:

For the Paschen series, the values of $n_1$ and $n_2$ in the expression $\Delta E = R h c \left( \frac{1}{n_1^2} - \frac{1}{n_2^2} \right)$ are:

In the Rutherford experiment,if light atoms are used instead of heavy elements,what change is observed in the results?