$1 \text{ Curie}$ is equal to

Explain the $\alpha$-decay process and give its appropriate example.

Explain the basic nuclear process by equation in $\beta$-decay.

The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter nucleus is an

For the $\beta^{+}$ (positron) emission from a nucleus,there is another competing process known as electron capture (an electron from an inner orbit,say,the $K$-shell,is captured by the nucleus and a neutrino is emitted).
$_{z}^{A} X + e^{-} \rightarrow _{z-1}^{A} Y + \nu$
Show that if $\beta^{+}$ emission is energetically allowed,electron capture is necessarily allowed,but not vice-versa.

The decay constant of the end product of a radioactive series is