Question

A radioactive element has a half-life of 2 days. Which fraction represents the amount of an original sample of this element remaining after 6 days?

Answer 1

N1/N= 1/(2^n)

Where N1= remaining amount after decay

N=original amount

n= th half life

after 6 days means n= 6/2=3

hence fraction=N1/N= 1/(2^3)=

" 1/8 "

is

answer

Answer 2

Given:

Half-life of radioactive element (t 1/2) = 2days, t = 6days

Amount of an original sample of this element remaining (R) =?

Solution:

n = t/t1/2 = 6/2 = 3

To calculate the fraction representing the amount of original sample of an element

$R=R'/2^n$

R/R'=1/2^3

R/R'=1/8

Thus, the fraction representing the amount of an original sample of the radioactive element remaining after 6 days is 1/8.