Question

The half-life of radioactive strontium-90 is 29 years. In 1960, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years does it take until only 6% of the original amount absorbed remains?

Answer 1

Answer:

117.7 years

Step-by-step explanation:

We have half life formula,

A=P$(0.5)^{\frac{t}{d} }$

Where ''t'' is number of years

d is half life period.

We know d=29

Where A=6% =0.06

P= 100%=1

Plug in the known values into the formula.

0.06= 1$(0.5)^{\frac{t}{29} }$

Divide both sides by 1.

It gives,

0.06=$(0.5)^{\frac{t}{29} }$

Take log on both sides

log 0.06= $\frac{t}{29}$ log(0.5)

Divide both sides by log 0.5

4.05889 = $\frac{t}{29}$

Multiply both sides 29

t =117.7079....

Approximately t= 117.7 years.