$A$ radioactive element $X$ emits six $\alpha$-particles and four $\beta$-particles,leading to the final product ${ }_{82}^{208} Pb$. The element $X$ is:

The intensity of gamma radiation becomes $1/8$th of its initial value after traveling a distance of $36 \, mm$. After traveling what distance (in $mm$) will the intensity become half?

$A$ $^{238}U$ nucleus decays by emitting an $\alpha$ particle of speed $v \ m/s$. The recoil velocity of the residual nucleus is (in $m/s$):

$A$ 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 $...... \, MeV$.

Which of the following interactions is responsible for beta decay?

$A$ certain radioactive material $_ZX^A$ starts emitting $\alpha$ and $\beta$ particles successively such that the end product is $_{Z-3}Y^{A-8}$. The number of $\beta$ and $\alpha$ particles emitted are