Theory of Radioactive Disintegration

The half life of a radioactive isotope is three hours. If the initial mass of the isotope were 256 g, the mass of it remaining undecayed after 18 hours would be

If $M$ is atomic mass, $A$ is a mass number, What is meaning of  $\frac{\left(M-A\right)}{A}$?

Define magic numbers of nucleus of an atom.

The half-life of ${}^{40}\mathrm{K}$ is $1.28\times {10}^9 \mathrm{years}.$ What mass of this nuclide (in mg) has an activity of $1.00 \mathrm{\mu Ci}?$

(Given ${\mathrm{N}}_{\mathrm{A}}=6.023\times {10}^{23}$)

Report your answer up to two places of decimal.

If $5 \mathrm{g}$ of a radioactive substance has ${\mathrm{t}}_{\frac{1}{2}}=14 \mathrm{h}, 20 \mathrm{g}$ of the same substance will have a ${\mathrm{t}}_{\frac{1}{2}}$ equal to

The rate of the process: $\mathrm{Cu}\to \mathrm{Ni}+{}_{+1}{}^0\mathrm{e}$

Radioactive disintegration rate is affected by

Half-life of a radioactive sample is $2\mathrm{x}$ years. What fraction of this sample will remain undecayed after $\mathrm{x}$ years?

One becquerel of radioactivity is equal to

The nuclide lying below the stability belt in $\mathrm{n}-\mathrm{p}$ graph does not disintegrate by

A radioactive nuclide generally disintegrates by $\mathrm{\alpha }-$emission when its $\mathrm{N}/\mathrm{P}$ ratio is

The number of stable isotopes is the least when the number of neutrons and protons in the isotopes are, respectively,

The binding energy per nucleon of ${}^{16}\mathrm{O}$ is $7.97 \mathrm{MeV}$ and that of ${}^{17}\mathrm{O}$ is $7.75 \mathrm{MeV}$. The energy in $\mathrm{MeV}$ required to remove a neutron from ${}^{17}\mathrm{O}$ is

Both technetium-$99$ and thallium-$201$ are used to image heart muscle in patients who may have heart problems. The half-lives are $6 \mathrm{h}$ and $73 \mathrm{h}$ respectively. What percent of radioactivity would remain for each of the isotopes after $2$ days?

Two radioactive elements $\mathrm{P}$ and $\mathrm{Q}$ have decay constant $10{\mathrm{\lambda }}_0$ and ${\mathrm{\lambda }}_0$. If initially they have same number of nuclei, the ratio of number of their undecayed nuclei will be $(1/\mathrm{e})$, after a time

The decay constant of a radio isotope is $\lambda$. If $A_1$ and $A_2$ are its activities at times $t_1$ and $t_2$, respectively, then the number of nuclei which have decayed during the time $\left(t_2-t_1\right)$ is

Find the weight of ${}^{57}Co$ inside the open container after $540$ days  if it initially weights $10 \mathrm{gm}$, has a half-life of $270 \mathrm{days}$ and decays by emitting $\beta$-particles.

In uranium series, what will be the decay constant of the stable end product of the series, if the decay constant of the parent nuclide is $\lambda$?

A bone sample is unearthed by an archaeologist and he wants to know the age of the bone. Her chemist friend determines that 45.3% of the initial amount of carbon-14 is present in the bone sample. If the half-life of carbon-14 is 5730 yrs, Determine the age (in years) of the bone.

One drug has radioactivity 80 dpm and after 20 minutes its activity is 40 dpm. How many number of atoms present initially ?