The number of beta particles emitted by a radioactive substance is twice the number of alpha particles emitted by it. The resulting daughter nucleus is an

Which one of the following is a possible nuclear reaction?

$A$ free neutron decays spontaneously into :

When a radioactive substance emits an $\alpha$-particle,its position in the periodic table is lowered by

In a radioactive decay process,the atomic number and mass number of the nucleus do not change. Which of the following is emitted during this process?

$A$ common example of alpha decay is ${ }_{92}^{238} U \longrightarrow{ }_{90}^{234} Th +{ }_{2}^{4} He + Q$. (Given: ${ }_{92}^{238} U = 238.05060 \, u$,${ }_{90}^{234} Th = 234.04360 \, u$,${ }_{2}^{4} He = 4.00260 \, u$,and $1 \, u = 931.5 \, MeV/c^2$). The energy released $(Q)$ during the alpha decay of ${ }_{92}^{238} U$ is $...... \, MeV$.