Question

Iodine-125 has a half-life of about 60 days.

How many milligrams of a 1500mg sample will remain after 180 days?

Answer 1

187.5 milligrams of a 1500 mg sample will remain after 180 days

Explanation:

Given:

Half life of Iodine-125 = 60 days

Initial amount of Iodine-125 present = 1500mg

To Find:

The amount of Iodine-125 present after 180 days

Solution:

Half- life the time taken for the radioactive substance to decay or reduce into half of its amount.

So,

After first 60 days

=>
`1500mg * (1)/(2) = 750mg`

After next 60 days i.e., after 120 days

=>
`750mg * (1)/(2) = 375mg`

After another 60 days i.e., after 180 days

=>
`375mg * (1)/(2) = 187.5mg`