If the quantity of a radioactive element is doubled,then its rate of disintegration per unit time will be

The half-life of radioisotopic bromine $-82$ is $36 \ hours$. The fraction which remains after one day is . . . . . . $\times 10^{-2}$. (Given $\text{antilog } 0.2006 = 1.587$)

The half-life period of a radioactive substance is $8 \ years$. After $16 \ years$,the mass of the substance will reduce from starting $16.0 \ g$ to ....... $g$.

The half-life of $10 \ g$ of a radioactive substance is $10 \ days$. The half-life of $20 \ g$ of the same substance is .......... $days$.

An element has a half-life of $1600 \ years$. The fraction of the mass left after $6400 \ years$ will be:

$A$ radioactive isotope has a half-life of $20 \ days$. If $100 \ g$ of the substance is taken,the weight of the isotope remaining after $40 \ days$ is ......... $g$.