Q 12-13-006NEETNEET 2021Top questionMedium
A radioactive nucleus $^A_ZX$ undergoes spontaneous decay in the sequence
$$^A_ZX \rightarrow {}_{Z-1}B \rightarrow {}_{Z-3}C \rightarrow {}_{Z-2}D$$
where Z is the atomic number of element X. The possible decay particles in the sequence are :
Answer: (D) $\beta^+,\ \alpha,\ \beta^-$
Concept. Identify each decay by the change in $Z$: $\beta^+$ lowers $Z$ by $1$, $\alpha$ lowers it by $2$, $\beta^-$ raises it by $1$.
Step 1. Each step.
- $Z \to Z - 1$: $\beta^+$.
- $Z - 1 \to Z - 3$: $\alpha$.
- $Z - 3 \to Z - 2$: $\beta^-$.
Answer. $\beta^+,\ \alpha,\ \beta^-$ (Option D).
Solution by Sreeraj P, M.Sc Physics