Question

1. The half-life of the radioactive element krypton-91 is 10 seconds. If 32

grams of krypton - 91 are initially present, how many grams are present
after 30 seconds? Show the decay function. Use A = A0ekt

Answer 1

4 g after 30 seconds.

Explanation:

After 10 seconds 32 * 1/2 = 16 g are present.

After 20 seconds 32 * (1/2)^2 = 8 g are present

After 30 seconds 32 * (1/2)^3 = 4 g are present.