The mass of a $${}_3^7Li$$ Li nucleus is 0.042 u less than the sum of the masses of all its nucleons. The binding energy per nucleon of $${}_3^7Li$$ nucleus is nearly

The energy of a hydrogen atom in the ground state is $$-$$ 13.6 eV. The energy of a He⁺ ion in the first excited state will be

An alpha nucleus of energy $${1 \over 2}$$ mv² bombards a heavy nuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to

In the nuclear decay given below

$${}_Z^AX \to {}_{Z + 1}^AY \to {}_{Z - 1}^{A - 4}B{}^ * \to {}_{Z - 1}^{A - 4}B,$$

the particles emitted in the sequence are