The intensity of gamma radiation emitted from a source is $I_0$. After passing through a lead sheet of thickness $36 \, mm$,its intensity becomes $I_0/8$. Find the thickness of the lead sheet in $mm$ when the intensity becomes $I_0/2$.

$A$ radioactive source is placed in a uniform electric field. If $\alpha, \beta$,and $\gamma$ particles are emitted,then $\alpha, \beta, \gamma$ particles correspond to which paths respectively?

An atomic nucleus $_{90}Th^{232}$ emits several $\alpha$ and $\beta$-radiations and finally reduces to $_{82}Pb^{208}$. It must have emitted:

$A$ radioactive decay can form an isotope of the original nucleus with the emission of which particles?

$A$ free neutron decays spontaneously into :

$A$ radio nuclide $A_1$ with decay constant $\lambda_1$ transforms into a radio nuclide $A_2$ with decay constant $\lambda_2$. If at the initial moment the preparation contained only the radio nuclide $A_1$,then the time interval after which the activity of the radio nuclide $A_2$ reaches its maximum value is: