Question

If a 200 g sample of Radon-220 has a half-life of 55 seconds. How much material is left after
220 seconds?
A 12.5 g
B) 25 g
c) 55 g
D) 100 g

Answer 1

The answer is A - 12.5 grams. Every 55 seconds, half of the Radon would decay. After 220 seconds, this process would have occurred 4 times.

Answer 2

The answer is B 12.5g