A radioactive substance has a half-life of 20 days what fraction the original radiation nuclei will remain after 80 days?
- (1)/32
-
(1)/16
- (1)/ 8
- (1)/4
The correct answer is: B
Explanation
80 days = 4 half lives (i.e 4 x 2odqs = 80 days)But the fraction always left by any radioactive material after 4half lives is (1/2)4 = (1)/16