Among the fundamental forces, which one of the following is the strongest force?

The electric potential at the surface of an atomic nucleus $(Z=50)$ of radius $9 \times 10^{-15} \,m$ is

$A$ reaction between a proton and $_8^{18}O$ that produces $_9^{18}F$ must also liberate:

The particles which can be added to the nucleus of an atom without changing its chemical properties are called:

$\pi$ mesons can be

Nuclear reactions are given as $(i)$ $(n, p) {}_{16}S^{32} \to {}_{15}P^{32}$,$(ii)$ $(p, \alpha) {}_{8}O^{16} \to {}_{9}F^{19}$,$(iii)$ ${}_{7}N^{14} + ? \to {}_{6}C^{14} + {}_{1}H^{1}$. The missing particles or nuclides in these reactions are respectively: