A mercury-198 nucleus is bombarded by a neutron, which causes a nuclear reaction

$$ n_0^1+\mathrm{Hg}_{80}^{198} \longrightarrow A u_{79}^{197}+X $$

What is the unknown product particle $X$ ?

Two deuterons are fused to form one alpha particle. If binding energy per nucleon of deuterium is 1.05 MeV and that of alpha particle is 7 MeV , what is the energy released in the formation of one alpha particle from the fusing of two deuterons?

An atom with one electron has ionization energy of 24 eV . An electron in this atom makes a transition from an excited energy level, where $\mathrm{E}=-15 \mathrm{eV}$, to the ground state. What is the wavelength of the emitted photon from this transition?

If the mass numbers of two nuclei are in the ratio $5: 2$ and their diameters are in ratio $2: 6$. Then their nuclear densities will be in the ratio