$^{22}Ne$ nucleus after absorbing energy decays into two $\alpha - $ particles and an unknown nucleus. The unknown nucleus is

In the nuclear decay given below 

$_z{X^A}{ \to _{z + 1}}{Y^A}{ \to _{z - 1}}{K^{A - 4}}{ \to _{z - 1}}{K^{A - 4}}$

the particles emitted in the sequence are

 A nucleus  $_n{X^m}$ emits one $\alpha$ particle and two $\beta$ particles. The resulting nucleus is

A nucleus of atomic mass $A$ and atomic number $Z$ emits ${M_1}$ particles. The atomic mass and atomic number of the resulting nucleus are

$\gamma$-rays radiation can be used to create electron-positron pair. In this process of pair production, $\gamma$-rays energy cannot be less than .......$MeV$

An element $A$ decays into element $C$ by a two step process :

$A \to B + {\;_2}H{e^4}$

$B \to C + \;2{e^ - }$

Then