The half-life of carbon-14 is about 5730 years. (That's 5,730 ±40 years, if more accuracy is desired.) A link can be found below for more information about radiocarbon, which is what we commonly call carbon-14.
Half of 14 is 7
Half of 14 equals 7.
the half-life of an carbon 14 is 5,730
The half-life of carbon-14 is 5730 years.
the half life of c-14 is 5,730 years
It is 14/2
Nitrogen-14 is stable (it's half-life is infinite)
14 is 7, twice. 14 is half of 28.
It is 14/2.
14