The activity of a radioactive substance is and at time and respectively

PHYSICS · Single correct · A Level · Physics · Nuclear physics · Nuclear physics

Problem

The activity of a radioactive substance is

A_1

and

A_2

at time

t_1

and

t_2

respectively. If

t_2 > t_1

, then the ratio of

\frac{A_2}{A_1}

is: (1)

e^{-\lambda(t_1+t_2)}

(2)

e^{\lambda(t_1-t_2)}

(3)

e^{\lambda(t_2-t_1)}

(4)

e^{t_2/t_1}