1/2 life of unstable isotope is 10,000 yrs, only 1/8 remains, how old is sample?

Question

if you could attach the equation used to solve this, i would appreciate it.

Answer 1

30,000 yrs

1/2 = 10,000 yrs.
1/2 of that = 1/4 = 20,000 yrs.
1/2 of that = 1/8 = 30,000 yrs.

1/8 = 2^-3.

So, the equation = 2 to the power of (-n) of sample = n*(1/2 life)

Answer 2

Well, after 10,000, you have 1/2 as much as you started with. After the next 10,000 years, you have 1/2 of that, or 1/4 what you started with. After another 10,000 years, you'll have 1/2 of that, or 1/8 of what you started with. So, after 30,000 years, only 1/8 remains.

Answer 3

Assume 1g of radioactive substance. After 1 half life there is 1/2 g left (10000 yr). Another half life yields 1/4 g (10000 yr). Another half life yields 1/8 g (10000 yr). Adding the 3 half lives it takes to get to 1/8 gives 30000 years.

Answer 4

(1/2)^n = 1/8
=> n = 3
therefore,
sample age = 3*10000 = 30 000 yrs

Answer 5

1/8 = 1/(2^3)

So this means that 3 half lives have elapsed.

So the sample is 30,000 years old.

Answer 6

a million/8 = a million/ 2^3 so 3 0.5 lives or 60 years. artwork it out: 1St. 0.5 existence, 2 many years, a million x a million/2, so a million/2 left 2nd. 0.5 existence 2 many years a million/2 x a million/2, so a million/4 left third. 0.5 existence 2 many years a million/4 x a million/2, so a million/8 left. notice which you multiply the quantity remaining via a million/2 for each era so something is the unique pattern x a million/2^(variety of 0.5 lives expired)

Answer 7

If Christian fundamentalists continue to gain power, the correct answer will be:

Radioactive decay is a trick of Satan which attempts to fool God fearing humans into believing that the universe is older than 8 thousand years.

Answer 8

30000 years

(1/2)^x=10000x

1/8 = (1/2)^3

10000(3) = 30000

Answer 9

Three half lives have passed.

Therefore it is 80000 years old.

Answer 10

30,000 years

and do your own damned homework next time.