Carbon dating is best suited for determining the age of fossils if their age in years is of the order of

Activity of a radioactive sample decreases to $(1/3)^{rd}$ of its original value in $3\, days$. Then, in $9\, days$ its activity will become

If $20\, gm$ of a radioactive substance due to radioactive decay reduces to $10 \,gm$ in $4 \,minutes,$ then in what time $80\, gm $ of the same substance will reduce to $10 \,gm$

Samples of two radioactive nuclides, $X$ and $Y$, each have equal activity $A_0$ at time $t = 0$ . $X$ has a half life of $24$ years and $Y$ a half life of $16$ years. The samples  are mixed together.What will be the total activity of the mixture at $t = 48$ years ?

If a radioactive material remains $25 \%$ after $16$ days, then its half life will be ......... days

Some nuclei of a radioactive material are undergoing radioactive decay. The time gap between the instances when a quarter of the nuclei have decayed and when half of the nuclei have decayed is given as:

(where $\lambda$ is the decay constant)