Question

An atomic nucleus $90Th^{232}$ emits several α and β radiations and finally reduces to$82Pb^{208}$. It must have emitted.

• A. 4α and 2β
• B. 6α and 4β
• C. 8α and 24β
• D. 4α and 16β

Answer 1

Answer: (B)

6α and 4β

Answer 2

$n_{\alpha} = \frac{A - A'}{4} = \frac{232 - 208}{4} = 6$

$n_{\beta} = 2n_{\alpha} - Z + Z' = 2 \times 6 - 90 + 82 = 4$