Suppose that a radioactive substance disintegrates completely in 10 days. Each day it disintegrates at a rate twice the previous day. Then after nine days the percentage of the material left to be disintegrated is

Options

A. a) 0.1
B. b) 0.25
C. c) 0.2
D. d) 0.5

Answer

D

Explanation

Afer 9 days the percentage of the radioactive material left to be disintegrated is 50% so that for further disintegration the rate of disintegration will be 100% and there will be complete disintegration of the material in 10 days