Question

if 250 mg of radioactive element decays to 200mg in 48 hours, find the half-life of the element

Answer 1

any particular decay formula?

Answer 2

I dont know thats why I am asking...

Answer 3

m(t)=m e^(-rt)

m(t) = amount after t hours
m = initial amount
r = rate
t = time

imma use this then
first we have to find the rate of decay, r, by substitute the given information

200 = 250 e^(-r48)
4/5 = e^(-r48)
ln(4/5) = -r48
ln(4/5)/(-48) = r

still with me? :d

Answer 4

okay

Answer 5

r = 0.0046

for the half life, it means m(t) = 1/2 m. so~

1 = 2 e^(-0.0046t)
1/2 = e^(-0.0046t)
ln(1/2) = -0.0046t
ln(1/2)/(-0.0046) = t

Answer 6

okayy

Answer 7

got it all? o.o"

Answer 8

yeah thank you