In the following equation representing $\beta^{-}$ decay,the number of neutrons in the nucleus $X$ is ${ }_{83}^{210} Bi \longrightarrow X + { }_{-1}^{0} e + \bar{\nu}$

Which of the following will have the highest penetrating power?

$A$ nucleus decays by ${\beta ^ + }$ emission followed by a gamma emission. If the atomic and mass numbers of the parent nucleus are $Z$ and $A$ respectively, the corresponding numbers for the daughter nucleus are respectively.

In a radioactive decay, neither the atomic number nor the mass number changes. Which of the following would be emitted in the decay process?

$A$ free neutron decays into a proton, an electron and

$A$ free neutron decays spontaneously into: