The electron emitted in beta radiation originates from

Out of the following, which one is not emitted by a natural radioactive substance?

Which waves are used in the treatment of cancer?

$A$ nucleus with mass number $184$ initially at rest emits an $\alpha$-particle. If the $Q$ value of the reaction is $5.5\, \text{MeV}$,calculate the kinetic energy of the $\alpha$-particle in $\text{MeV}$.

In a radioactive decay chain reaction,${ }_{90}^{230} Th$ nucleus decays into ${ }_{84}^{214} Po$ nucleus. The ratio of the number of $\alpha$ to number of $\beta^{-}$ particles emitted in this process is. . . . .

Beta rays emitted by a radioactive material are