The decay curve for any radioactive substance is the same form as the carbon-14 decay curve.The only difference is the time axis.

1.  The decay curve for any radioactive substance is the same form as the carbon-14 decay curve. The only difference is the time axis. Approximately how many half-lives does it appear to take a radioactive sample to be essentially dead (activity equals approximately zero)? (Carbon-14 has a half-life of 7530 years.)