If an ancient campfire were analyzed, was found to have only about one-eighth the carbon-14 that is normally found in living things, how long ago was that campfire extinguished? Answer in units of y.

17047.54 years or 17048 y

Explanation:

From;

0.693/t1/2 = 2.303/t log (Ao/A)

Where;

t1/2=half-life of the carbon-14 =5670 years

t= time elapsed

Ao= activity of living C-14

A= activity if the sample under study

But A= 1/8 Ao

Hence;

0.693/5670= 2.303/t log(Ao/1/8Ao)

1.22×10^-4 = 2.303/t log 8

1.22×10^-4 = 2.0798/t

t= 2.0798/1.22×10^-4

t= 17047.54 years

photocells convert light energy to electricity

it has to be b, about 97 percent.