${}_{19}^{39}K$ and ${}_{20}^{40}Ca$ are :

Two nuclei have mass number in the ratio 1:8, what is the ratio of their nuclear radii?

The radius of ${}_{13}^{27}\text{Al}$ is $3.6$ Fermi. Find the radius of ${}_{52}^{125}\text{Te}$

The energy equivalent to $1kg$ of matter in (in Joule)

The energy of the reaction
$L{i}^7+p⟶2_{2}H{e}^4$
if the binding energy per nucleon in $L{i}^7$ and $H{e}^4$ nuclei are $5.60MeV$ and $7.06MeV$, respectively, is :

The half-life of ${}^{238}$U for $\alpha$- decay is $4.5\times 10^9$ years. The number of disintegration per second occur in 1g of ${}^{238}$U is
(Avogadro's number=6.023 10${}^{23}mo{l}^{-1}$)

How many $\alpha$ and $\beta -particles$ will be emitted when ${}_{90}T{h}^{232}$ changes into ${}_{82}P{b}^{208}$?

The average binding energies of deuterium and $\alpha$ -particle are 1.12 MeV and 7.1MeV respectively. The energy that liberates in the reaction ${}_1{H}^2$+${}_1{H}^2$ $\to$ ${}_{2}H{e}^4$ is $\underline{}$ MeV.