A nucleus of $^{238}_{92}\text{U}$ undergoes a sequence of decays by releasing $\alpha$-particles and $\beta^{-}$ particles, and it finally changes into a nucleus of $^{206}_{82}\text{Pb}$. How many $\alpha$-particles and how many $\beta^{-}$ particles are emitted in the decay chain?
Physics 9702 · AS & A Level · Physical quantities