When a $\beta $-particle is emitted from the nucleus of an element,then:

In the reaction $_{93}Np^{239} \xrightarrow{} _{94}Pu^{239} + (?)$,the missing particle is

$A$ radium $_{88}Ra^{224}$ isotope,on emission of an $\alpha$-particle,gives rise to a new element whose mass number and atomic number will be:

Which of the following processes does not occur via $\alpha$-decay?

$A$ radioactive nuclide $X$ decays at the rate of $1.00 \times 10^5 \ disintegration \ s^{-1} \ g^{-1}$. Radium decays at the rate of $3.70 \times 10^{10} \ disintegration \ s^{-1} \ g^{-1}$. The activity of $X$ in millicuries $g^{-1}$ $(mCi \ g^{-1})$ is

How many alpha particles are emitted in the nuclear transformation
$_{84}Po^{215} \xrightarrow{} _{82}Pb^{211}$?