A radioactive nucleus can decay by two different processes. Half-life for the first process is $3.0\, hours$ while it is $4.5\, hours$ for the second process. The effective half- life of the nucleus will be $.........\,hours.$
$3.75$
$0.56$
$0.26$
$1.80$
The $S.I.$ unit of radioactivity is
Consider an initially pure $M$ gm sample of$_ A{X}$, an isotope that has a half life of $T$ hour, what is it’s initial decay rate ($N_A$ = Avogrado No.)
The ratio activity of an element becomes $\frac{{1}}{{64}} th$ of its original value in $60\, sec$. Then the half life period is ............$sec$
A count rate meter shows a count of $240$ per minute from a given radioactive source. One hour later the meter shows a count rate of $30$ per minute. The half-life of the source is ..........$min$
The mean life of a radioactive material for alpha decay and beta decay are, respectively, $1620$ years and $520$ years. What is the half life of the sample (in years) ?