A radioactive sample disintegrates via two independent decay processes having half lives $T _{1 / 2}^{(1)}$ and $T _{1 / 2}^{(2)}$ respectively. The effective half- life $T _{1 / 2}$ of the nuclei is

Radioactive substances do not emit

$A$ and $B$ are two radioactive substances whose half lives are $1$ and $2$ years respectively. Initially $10\, g$ of $A$ and $1\,g$ of $B$ is taken. The time (approximate) after which they will have same quantity remaining is ........... $years$

At any instant the ratio of the amount of radioactive substances is $2 : 1$. If their half lives be respectively $12$ and $16$ hours, then after two days, what will be the ratio of the substances

In Fig. $X$ represents time and $Y$ represents activity of a radioactive sample. Then the activity of sample, varies with time according to the curve

There are $10^{10}$ radioactive nuclei in a given radioactive element, Its half-life time is $1\, minute.$ How many nuclei will remain after $30\, seconds?$

$(\sqrt{2}=1.414)$