Question

Strontium-90 has a half-life of 29 years. In how many years will a 1 kg sample of strontium-90 decay and reduce to 0.25 kg of strontium-90?

Answer 1

Answer:

The weight of Strontium-90 will reduce to $0.25$ Kg in $58$ years.

Explanation:

Given -

Radioactive isotope sample of Strontium-90 $= 1$Kg

Half life of Strontium-90 $= 29$ years

After first half life (i.e 29 years), the weight of Strontium-90

$= \frac{1}{2}\\= 0.5$ Kg

After second half life (i.e 58 years), the weight of Strontium-90

$= \frac{0.5}{2}\\= 0.25$ Kg

Thus, the weight of Strontium-90 will reduce to $0.25$ Kg in $58$ years.

Answer 2

58 years.
1kg - 0 years
0.5kg - 29 years
0.25kg - 58 years