Question

Oxygen 22 has a half life of 2.25 seconds. What percent of the sample is left after 2.25 seconds?

Answer 1

Answer:

50 because it’s a ratio problem

Explanation:

Answer 2

Answer:

So we got 50% left after 2.25 seconds

Explanation:

The left sample is given by

$m=m_{0}.2^\frac{-t}{T}$

where T is the half-life

After 2.25 s

$m=m_{0}.2^\frac{-2.25}{2.25}=m_{0}.\frac{1}{2}$