Question

A sample of F-18 has half life 110 min .How long does it take for 99% of F-18 to decay ​

Answer 1

Explanation:

From law of radio activity,N=N

0

e

−λt

Here decay constant, λ=

t

1/2

0.693

=0.693/110=0.0063min

−1

Let, N

0

=100 so rest amount after decay at t N=(100−99)=1

So, 1=100e

−(0.0063)t

or e

0.0063t

=100 or 0.0063t=ln100=ln10

2

=2ln10

or t=730 min