A solution containing active cobalt ${}_{27}^{60}Co$ having activity of $0.8\,\mu Ci$ and decay constant $\lambda $ is injected in an animal's body. If $1 \,cm^3$ of blood is drawn from the animal's body after $10\, hrs$ of injection, the activity found was $300\, decays$ per minute. What is the volume of blood that is flowing in the body?..........$litres$ ( $ICi = 3.7 \times 10^{10}$ decay per second and at $t = 10\, hrs$ ${e^{ - \lambda t}} = 0.84$ )

The fraction $f$ of radioactive material that has decayed in time $t$, varies with time $t$. The correct variation is given by the curve

The decay constant of the end product of a radioactive series is

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

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

Half lives for $\alpha$ and $\beta$ emission of a radioactive material are $16$ years and $48$ years respectively. When material decays giving $\alpha$ and $\beta$ emission simultaneously then time in which $\frac{3}{4}$ th of the material decays is ....... years