The half-life of a radioactive substance is $120$ days. After $480$ days,the amount of $4 \ g$ of the substance remaining will be: (in $g$)

$A$ wood piece is $11460$ years old. What is the fraction of $^{14}C$ activity left in the piece? (Half-life period of $^{14}C$ is $5730$ years)

If $12 \ g$ of a sample is taken,and $6 \ g$ of the sample decays in $1 \ hr$,the amount of the sample showing decay in the next hour is ........ $g$.

The activity of carbon-$14$ in a piece of an ancient wood is only $12.5\%$. If the half-life period of carbon-$14$ is $5760 \, years$,the age of the piece of wood will be $(\log \, 2 = 0.3010)$

What is the order of radioactive decay of a substance?

An element has a half-life of $1600 \ years$. The fraction of the mass left after $6400 \ years$ will be: