What is the order of a radioactive decay reaction?

For a radioactive substance with a half-life period of $500$ years,the time required for the complete decay of $100 \ mg$ of it would be:

The half-life period $t_{1/2}$ of a radioactive element is $N$ years. The period of its complete decay is

In the case of a radioisotope,the value of $T_{1/2}$ and $\lambda$ are identical in magnitude. The value is

The half-life for radioactive decay of $^{14}C$ is $5730 \ years$. An archaeological artifact containing wood had only $80\%$ of the $^{14}C$ found in a living tree. The age of the sample is ....... $years$.

$A$ wooden artifact and a freshly cut tree have carbon activity of $7.6$ and $15.2 \ min^{-1} g^{-1}$ respectively. Given the half-life $(t_{1/2})$ of carbon is $5760$ years,the age of the artifact is: