A radioactive substance has an average life of `5` hours. In a time of `5` hours

Options

A. Half of the active nuclei decay
B. Less than half of the active nuclei decay
C. More than half of the active nuclei decay
D. All active nuclie decay

Answer

C

Explanation

( c) If `lamda` is the decay constant of a radioactive substance then average life `= (1)/(lamda)`
Also half life `(0.693)/(lamda) = 0.693 xx` (Average life)
In single average life, more than `63 %` of radioactive.