Question #03416

2 Answers
Apr 14, 2017

11460 years.

Explanation:

N/(N_0) = (1/2)^n

Where, N_0 = Original amount of radioactive nuclei present.

N = Nuclei present at that instant.

n = t/(T)

T = Half life of Carbon-14
Half life of C-14 is 5730 years.

t = Time in which the particular number of nuclei has disintegrated.

:. N/(N_0) = (25/100)

Which is,

(1/2)^n = (1/4)

(1/2)^n = (1/2)^2

t/T = 2

t = T × 2

t = 5730 × 2

t = 11460 years

Apr 19, 2017

11460 years old

Explanation:

At time t=0, we have 100% of the radioactive ""^14"C" isotope.

The half-life of ""^14"C" is 5730 years. This means that at t=5730 years, only 50% of the original ""^14"C" remains.

Taking half of 50%, we see that the next half life will occur at t=2xx5730=11460 years. At this point in time, only 25% of the ""^14"C" will remain.