The most penetrating radiation out of the following is
$X-$ rays
$\beta -$ rays
$\alpha - $ particles
$\gamma - $ rays
The radioactive decay of uranium into thorium is expressed by the equation $_{92}^{238}U \to _{90}^{234}Th + X,$ where $'X'$ is
A nucleus of an element ${}_{84}{X^{202}}$ emits an $\alpha $-particle first, $\beta $ -particle next and then a gamma photon. The final nucleus formed has an atomic number
The $\beta$-particles of a radioactive metal originate from
The particles emitted by radioactive decay are deflected by magnetic field. The particles will be
A nucleus of lead $Pb _{82}^{214}$ emits two electrons followed by an $\alpha$-particle. The resulting nucleus will have