Which one of the following nuclei has shorter mean life?

In Rutherford experiment, for head-on collision of $$\alpha$$-particles with a gold nucleus, the impact parameter is

Frequency of revolution of an electron revolving in $$n$$th orbit of $$\mathrm{H}$$-atom is proportional to

A hydrogen atom is ground state absorbs $$10.2 \mathrm{~eV}$$ of energy. The orbital angular momentum of the electron is increased by