Question

What is that mean that half life of carbon -14 is 5700 years?

Answer 1

That means that half of it would be gone after `5700` years.

Explanation:

Consider a lump of `1 \ "kg"` of `""^14C`. Since it has a half-life of `5700` years, then there would only be half of it after that time, i.e. there will only be `500 \ "g"` of `""14^C` after `5700` years, and it is said to have elapsed one half-life.

After another `5700` years, half of it would be gone again, and only `250 \ "g"` would remain after `5700xx2=11400` years in total.

And that process keeps continuing until the number becomes infinitesimally small.

Hope this helps!

Answer 2

Half-life (symbol `t_("1/2")`) is the time required for a quantity to reduce to half its initial value.

Half life of `""^12"C"` is `5700` years. It means if we take `"N"_0` amount of `""^12"C"` then the time required for it to reduce to half (i.e `"N"_0/2`) is `5700` years.