Q. The plot of the number $(N)$ of decayed atoms versus activity $(A)$ of a radioactive substance is
A)
B)
C)
D)
Explanation
(d) $N = N_{0}e^{- \lambda t}$ and $A = A_{0}e^{- \lambda t} = \lambda N_{0}e^{- \lambda t}$
$\therefore N_{decayed} = N_{0} - N = N_{0} - N_{0}e^{- \lambda t} \Rightarrow N_{decayed} = N_{0} - \frac{A}{\lambda}$
This is equation of straight line with negative slope
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.