Some nuclei of a radioactive material are undergoing radioactive decay. The time gap between the instances when a quarter of the nuclei have decayed and when half of the nuclei have decayed is given as:
(where $\lambda$ is the decay constant)
$\frac{2 \ln 2}{\lambda}$
$\frac{1}{2} \frac{\ln 2}{\lambda}$
$\frac{\ln \frac{3}{2}}{\lambda}$
$\frac{\ln 2}{\lambda}$
Radioactivity is
The half-life of a radioactive substance is $3.6$ days. How much of $20\, mg$ of this radioactive substance will remain after $36$ days ............. $mg$
If half-life of a radioactive atom is $2.3\, days$, then its decay constant would be
Assertion : If the half life of a radioactive substance is $40\, days$ then $25\%$ substance decay in $20\, days$
Reason : $N = {N_0}\,{\left( {\frac{1}{2}} \right)^n}$
where, $n = \frac{{{\rm{time\, elapsed}}}}{{{\rm{half \,life \,period}}}}$
A radioactive nucleus ${ }_{\mathrm{Z}}^{\mathrm{A}} \mathrm{X}$ undergoes spontaneous decay in the sequence
${ }_{\mathrm{Z}}^{\mathrm{A}} \mathrm{X} \rightarrow {}_{\mathrm{Z}-1}{\mathrm{B}} \rightarrow {}_{\mathrm{Z}-3 }\mathrm{C} \rightarrow {}_{\mathrm{Z}-2} \mathrm{D}$, where $\mathrm{Z}$ is the atomic number of element $X.$ The possible decay particles in the sequence are :