Out of the following,choose the ray which does not travel with the velocity of light.

Arrange the radioactive radiations in increasing order of their ionizing power and penetrating power.

$A$ radioactive nucleus undergoes a series of decays according to the scheme
$A \xrightarrow{\alpha} A_1 \xrightarrow{\beta} A_2 \xrightarrow{\alpha} A_3 \xrightarrow{\gamma} A_4$
If the mass number and atomic number of $A$ are $180$ and $72$,respectively,then what are these numbers for $A_4$?

An element $A$ decays into element $C$ by a two-step process:
$A \to B + {\;_2}He^4$
$B \to C + 2e^-$
Then:

${ }_{92} U^{235}$ undergoes successive disintegrations with the end product of ${ }_{82} Pb^{203}$. The number of $\alpha$ and $\beta$ particles emitted are

Which of the following is not emitted during the radioactive decay of a radioactive element?