Question

If you start with 200 grams of an isotope, how many grams would be left after 40 years if the half-life of the isotope is 10 years?

Answer 1

Answer:

12.5 grams

Explanation:

From the question,

E' = E/2⁽ⁿ/a⁾....................... Equation 1

Where E' = mass left, E = Original mass, n = time, a = half-life.

Given: E = 200 grams, n = 40 years, a = 10 years.

Substitute these values into equation 1

E' = 200/2⁽40/10⁾

E' = 200/2⁴

E' = 200/16

E' = 12.5 grams.

Hence 12.5 grams of the isotope will be left.