An anthropologist finds there is so little carbon-14 remaining in a prehistoric bone that instruments cannot measure it. this means there is less than 0.2% of the amount of carbon-14 the bones would have contained when the person was alive. how long ago did the person die? (the constant for carbon-14 is 0.00012.)
answer
13,411 years
22,491 years
45,020 years
51,788 years

The person died 51,788 years ago.

Explanation:

Let the initial amount of carbon-14 in the body when person was alive =

Amount of carbon-14 left after t years =

t = time elapsed

Decay constant of carbon-14=

t = 51,788.40 years ≈ 51,788 years

Since the carbon-14 in less than 0.02 % in the body which means the person must have died 51,788  years ago.

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current