The half life of a radioactive substance is 24 hours. Time required for 12.5% of the original radioactive substance W remain is

Options

A. 1 day
B. 2 days
C. 3 days
D. 4 days

Answer

C

Explanation

`t_(1//2)=24` hrs =1 day
`lambda=(0.693)/(t_(1//2))=0.693 "day"^(-1)`
`t=(2.303)/(t_(1//2))"log"(N_(0))/(N)`
`=(2.303)/(0.693)"log"(100)/(12.5)=(2.303)/(0.693)"log" 8`
= 3 days