Question

If the original mass of the radioactive material is 500 grams, what will be its mass after 6 billion years?

3.4 grams
7.8 grams
15.6 grams
31.2 grams

Answer 1

@shamim

Answer 2

@Hashir

Answer 3

@bahrom7893

Answer 4

can we agree that after 2 billion years, the sample amount decreased to 25%?

if so, then we can say that it's half-life is 1 billion years.
(because 100% (1/2) = 50%(1/2)= 25% thats 2 half-lives)

so if you have 500g, and the half-life is 1 billion years, then:

\[500(\frac{ 1 }{ 2 })^n\]

n is the number of half-lives.

Answer 5

no problem!