Question

.Instructions:Select the correct answer. The half-life of helium-5 is 7.6 × 10-22 seconds, and the half-life of helium-9 is 7 × 10-21 seconds. Approximately how many times greater is the half-life of helium-9 than that of helium-5? 2 times 7 times 9 times 11 times

Answer 1

The half-life of helium-5 is 7.6 × 10^{-22} seconds, and the half-life of helium-9 is 7 × 10^{-21} seconds.

Approximately
`(7 \cdot 10^(-21))/(7.6\cdot 10^(-22)) = (7)/(7.6\cdot 10^(-1)) = (7)/(0.76) =9` the half-life of helium-9 is greater than that of helium-5.
Answer: 9 times.