Question

CALCULATING HALF LIFE

A sample of cobalt-60 has an activity of 2000 Bq. What will the activity be after 10 years? Cobalt-60 has a halflife of 5 years.

please help i have been stuck on this for a long time.

Answer 1

N = 500Bq

Step-by-step explanation:

No = 2000Bq

Time (T) = 10years

T½ = 5 years.

N = ?

T½ = In2 / λ

T½ = 0.693 / λ

λ = 0.693 / t½

λ = 0.693 / 5

λ = 0.1386

The ratio between the two activities is

(N / No) = e⁻^λt

N = No * e⁻^λt

N = 2000 * e^⁻⁰.¹³⁸⁶ * ¹⁰

N = 2000 * e⁻¹.³⁸⁶

N = 2000 * 0.25

N = 500Bq

The activity of Co-60 after 10 years would be 500Bq