A radioactive isotope(h=4.5days) was prepared. This isotope was used 14 days later when it had an activity of 6000000 Bq. What was the activity of this isotope when initially prepared?

Answer 1

(Initial activity)*(0.5)^(14/4.5) = 6*10^7 Bq

Inital activity = 6*10^7*2^3.111
= 5.2*10^8 Bq

Answer 2

The answer on my handout is 5.18 x 10^7

Answer 3

I read your 6000000 incorrectly as 6*10^7. Using commas or scientific notation would have helped me read the string of zeros.

The handout answer is correct.