Question

Plutonium-240 decays according to the function http://i.imgur.com/31BwyAC.png. How long will it take 24 grams of plutonium-240 to decay to 20 grams?
1,660 years

1.06 years

80.11 years

.00048 years

Answer 1

what is the halflife of plutonium 240?

Answer 2

umm not sure

Answer 3

without the half life it's not possible to answer the question

Answer 4

according to wikipedia its 6563 years so we can work it out based on this.
have you tried to work it out?

Answer 5

i don't know how to solve for the halflife

Answer 6

we have to go with 6563 yrs because your question doesn't provide us with a half life
so we start by working out the k value in the equation

for the half life we re-arrange the equation to q(t)/q(0) = e^-kt

and q(t)/q(0) = 1/2 (for the half life) and t= 6563

so we have e^-6563k = 1/2 and now we solve for k

can you do that?

Answer 7

idk how sorry

Answer 8

Use log rules!