If in the case of a radioisotope the value of half-life $(T_{1/2})$ and decay constant $(\lambda)$ are identical in magnitude,then their value should be

${ }^{227}Ac$ has a half-life of $22 \, years$ with respect to radioactive decay. The decay follows two parallel paths: ${ }^{227}Ac \longrightarrow { }^{227}Th$ and ${ }^{227}Ac \longrightarrow { }^{223}Fr$. If the percentage of the two daughter nuclides are $2.0$ and $98.0$,respectively,the decay constant (in $year^{-1}$) for ${ }^{227}Ac \longrightarrow { }^{227}Th$ path is closest to

$A$ certain nuclide has a half-life period of $30 \ minutes$. If a sample containing $600$ atoms is allowed to decay for $90 \ minutes$,how many atoms will remain?

What is the percentage of a radioactive element decayed after $20 \ s$ if its half-life is $4 \ s$?

$A$ substance of which $1 \ g$ is taken,after one half-life period,what fraction of it is left?

The half-life of a radioactive isotope is $3 \ hr$. The value of its disintegration constant is: (in $hr^{-1}$)