A radioactive substance has a half-life of 20 days what fraction the original radiation nuclei will remain after 80 days?
-
A.
(1)/32 -
B.
(1)/16 -
C.
(1)/ 8 -
D.
(1)/4
Correct Answer: Option 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