The reaction $_5B^8 \to _4Be^8 + _1e^0$ is due to

Which is not emitted by a radioactive substance?

The number of $\alpha$ and $\beta$-particles emitted in the nuclear reaction $_{92}U^{238} \to _{90}Th^{234} \to _{91}Pa^{234}$ are respectively:

If $_{92}U^{236}$ nucleus emits one $\alpha$-particle,the remaining nucleus will have

The atomic number of a radioactive element increases by one unit in:

The $_{88}Ra^{226}$ is