The starting isotope and the end product isotope of actinium series are:

Q. The isotope ${}_{92}^{235}U$ decays in a number of steps to an isotope of ${}_{82}^{207}Pb$. The groups of particles emitted in this process will be:

Q. ${}_{92}^{235}U$ decays with emission of $\alpha$ and $\beta -$ particles to form ultimately ${}_{82}^{207}Pb$. How many $\alpha -$ and $\beta -$particles are emitted per atom of $Pb$ produced?

Q. Estimate the age of a rock which is found to contain $5\times {10}^{-5}$ mL of helium at STP and $3\times {10}^{-7}$ g of uranium. ($T_{50}$ of ${}_{92}^{238}U$ is $4.51\times {10}^9$ yr and each ${}_{92}^{238}U$ is converted into ${}_{82}^{206}Pb$
Plan ${}_{92}^{238}U{⟶}_{82}^{206}Pb+6\beta +8\alpha \left(helium\right)$
We take the equation $\left[\frac{\left[Pb\right]}{\left[U\right]}+1\right]=(2{)}^y$
where $\frac{\left[Pb\right]}{\left[U\right]}$ is the molar ratio, $y=\frac{t}{T_{50}}$

Q. ${}_{90}^{232}Th$ disintegrates to ${}_{82}^{208}Pb$. How many of $\beta$-particles are evolved?

Q. The total number of $\alpha$ and $\beta$ particles emitted in the nuclear reaction:
${}_{92}^{238}U⟶$ ${}_{82}^{214}Pb$ are: