Question

The half - life technetium - 99 is 6 hours. how much of a 192 mg sample will have decayed after 30 hours?

Answer 1

Answer: -

6 mg

Explanation: -

Initial amount N₀ = 192 mg

Half life = 6 hours.

Time given = 30 hours

Number of half lives =
`(30 hours)/(6 hours)`

= 5

Amount present after 30 hours = N₀ x [
`(1)/(2)`]
`^(Number of half lives)`

Amount present after 30 hours = 192 mg x [
`(1)/(2^5)`]

= 6 mg