The nuclide $^{133}I$ is radioactive,with a half-life of $8.04 \, days$. At noon on $January \, 1$,the activity of a certain sample is $600 \, Bq$. The activity at noon on $January \, 24$ will be

If the undecayed fraction of a radioactive sample is $7/8$ after $6$ days,what will be the undecayed fraction after $10$ days?

Give the different units of radioactivity and define them.

The half-life of a radioactive element is $10 \ h$. The fraction of initial radioactivity of the element that will remain after $40 \ h$ is

Ten percent of a radioactive sample has decayed in $1$ day. After $2$ days,the decayed percentage of nuclei will be ...... $\%$

$A$ certain radioactive element disintegrates with a decay constant of $7.9 \times 10^{-10} / s$. At a given instant of time,if the activity of the sample is equal to $55.3 \times 10^{11}$ disintegration/second,then the number of nuclei at that instant of time is: