Question

The half-life of cobalt-60 is 5.26 years. If 50 grams are left after 15.78 years, how many grams were in the original sample?

Answer 1

Answer:

Explanation:

Half life  = 5.6

no of half life in 15.78 years = 15.78 / 5.26

= 3 .

$N = N_0(\frac{1}{2})^n$

N₀ is original mass , N is mass after n number of half lives.

Inserting the given data in the equation above

$50 = N_0(\frac{1}{2})^3$

N₀ = 50 x 2³

= 400 gm .

original sample will contain 400 gms of sample.