Tritium undergoes radioactive decay giving

Which of the following statements is not true for radioactive decay?

Of the following radiations,the one most easily stopped by air is

After losing a number of $\alpha$ and $\beta$ particles,$_{92}U^{238}$ changed to $_{82}Pb^{206}$. The total number of particles lost in this process is

Consider the radioactive disintegration ${}_{82}A^{210}$ $\rightarrow B$ $\rightarrow C$ $\rightarrow {}_{82}D^{206}$. The sequence of emission can be

During the emission of a $\beta$-particle,what happens to the nucleus?