Question 1111909
 :
If 35 mg of a radioactive element decays to 10mg in only 24 hours,
 what is its half life?
:
the radioactive decay formula;
 A = Ao*2^(-t/h)
where:
A = amt remain after t time
Ao = initial amt of the substance
t = time of decay
h = half-life of substance
:
A = 10
A = 35
t = 24 hrs
find h
35*2^(-24/h) = 10
2^(-24/h) = 10/35
2^(-24/h) = 2/7
log equiv of exponents
{{{-24/h}}}log(2) = {{{log(2/7)}}}
{{{-24/h}}} = {{{log(2/7)/log2)}}}
using the calc
{{{-24/h}}} = -1.807355
h = {{{(-24)/(-1.807355)}}}
h = +13.28 hrs is the half life of the substance