Question

If a radioactive isotope has a half-life of 6 hours and 12 milligrams is initially present, how much will

be present in 24 hours?

Answer 1

Answer:0.75 milligrams will be present in 24 hours

Explanation:

Step 1

The formula for radioactive decay can be written as

N(t)=No (1/2)^(t/t 1/2)

where

No= The amount of the radioactive substance at time=0=milligrams

t 1/2= the half-life= 6 hours

t=24 hours

N(t) = the amount at time t

Step 2--- Solving

N(t)=No (1/2)^(t/t 1/2)

=N(t)=12 x ( 1/2) ^ (24/6)

= 12 x (1/2) ^4

= 12 x 0.0625

= 0.75 milligrams