A small quantity of solution containing $Na^{24}$ radio nuclide of activity $1$ microcurie is injected into the blood of a person. A sample of the blood of volume $1\, cm^3$ taken after $5$ hours shows an activity of $296$ disintegration per minute. What will be the total volume of the blood in the body of the person. Assume that the radioactive solution mixes uniformly in the blood of the person ……… $liter$

(Take $1$ curie $= 3.7 × 10^{10}$ disintegration per second and ${e^{ – \lambda t}} = 0.7927;$ where $\lambda$= disintegration constant)

$10\, gm$ of radioactive material of half-life $15$ year is kept in store for $20$ years. The disintegrated material is …………$gm$

A freshly prepared sample of a radioisotope of half-life $1386 \ s$ has activity $10^3$ disintegrations per second. Given that In $2=0.693$, the fraction of the initial number of nuclei (expressed in nearest integer percentage) that will decay in the first $80 \ s$ after preparation of the sample is :

If the mass of a radioactive sample is doubled, the activity of the sample and the disintegration constant of the sample are respectively

The half life of radioactive Radon is $3.8\, days$. The time at the end of which $1/20^{th}$ of the Radon sample will remain undecayed is  ………… $days$ (Given $log_{10}e = 0.4343$ )