Modern Physics Ques 143
- A uranium nucleus (atomic number $92$ , mass number $238$) emits an alpha particle and the resulting nucleus emits $\beta$-particle. What are the atomic number and mass number of the final nucleus?
$(1982,2 M)$
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Answer:
Correct Answer: 143.(a) $91 \quad $ (b) $234$
Solution:
Formula:
- ${ } _{92} U^{238} \stackrel{\alpha \text {-decay }}{\rightarrow}{ } _{90} X^{234} \stackrel{\beta \text {-decay }}{\rightarrow}{ } _{91} Y^{234}$
During an $\alpha$-decay atomic number decreases by $2 $ and mass number by $4$ . During a $\beta$-decay, atomic number increases by $1$ while mass number remains unchanged.
BETA
