Question

Scintillatium has a halflife of 16 minutes. if a sample has 800 grams, find a formula for its mass after t minutes.

Answer 1

Halflife is the time needed for a radioactive molecule to decay half of its current mass. If t is the time elapsed, the formula for the halflife would be:
final mass= original mass *
`(1)/(2) ^{(t)/(halflife)`

If you put the information of the problem into the formula, the equation will be:
final mass= original mass *
`(1)/(2) ^{(t)/(halflife)`
final mass= 800g *
`(1)/(2) ^{(t)/(16 min)`