Question

Gold-192 is a radioactive isotope with a half-life of 4.95 hours. How long will it take for a 15 gram sample of Gold-192 to decay until only 3 grams remain?
a. about 11.5 hours

b. about 24.75 hours

c. about 7.92 hours

d. about 2.13 hours

Answer 1

The answer should be A. In order to solve these half-life problems, I encourage you to find an algebra calculator online, and plug in these numbers. The remaining grams goes in front, so 3.

The entire equation should look something like 3 = 15(1/2)^t/4.95

The 4.95 represents how long it takes before the sample halves, t is your answer, 1/2 represents the value halving every 4.95 hours, 15 is the initial sample size, and 3 is the end result that remains.

The overall answer should be about 11.5 hours, as per an algebra calculator.

Hope this helps solve any other similar problems