Question

The ratio of ${}^{235}U$ to ${}^{238}U$ in natural uranium deposits today is $0.0072$. What was this ratio $2.0\times 10^9$ year ago? The halflives of the two isotopes are $7.04\times 10^8$ year and $44.7\times 10^8$ year, respectively.

• A. $4.8\%$
• B. $6.9\%$,
• C. $1.2\%$
• D. $3.8\%$

Answer 1

Answer: (D)

Correct answer is (d) $3.8\%$