In saloons, there is always a characteristics smell due to the ammonia-based chemicals used in hair dyes and other products. Assume the initial concentration of ammonia molecules to be $1000 \,molecules/ m ^3$. Due to air ventilation, the number of molecules leaving in one minute is one tenth of the molecules present at the start of that minute. How long will it take for the concentration of ammonia molecules to reach $1 \,molecule / m ^3$ ?
$7$ minutes
$70$ minutes
$100$ minutes
Very long time which cannot be calculated.
The half life of the isotope $_{11}N{a^{24}}$ is $15 \,hrs$. How much time does it take for $\frac{7}{8}th$ of a sample of this isotope to decay.........$hrs$
The half life of a radioactive sample undergoing $\alpha$ - decay is $1.4 \times 10^{17}$ s. If the number of nuclei in the sample is $2.0 \times 10^{21}$, the activity of the sample is nearly
The disintegration rate of a certain radioactive sample at any instant is $4250$ disintegrations per minute.$10$ minutes later, the rate becomes $2250$ disintegrations per minute. The approximate decay cons $.........\min^{-1}$
Who invented radioactivity ?
A radioactive material has a half life of $10$ days. What fraction of the material would remain after $30$ days