JEE PYQ: Nuclear Physics Question 26
Question 26 - 2019 (10 Jan Shift 1)
Using a nuclear counter the count rate of emitted particles from a radioactive source is measured. At $t = 0$ it was 1600 counts per second and $t = 8$ seconds it was 100 counts per second. The count rate observed, as counts per second, at $t = 6$ seconds is close to:
(1) 200
(2) 150
(3) 400
(4) 360
Show Answer
Answer: (1)
Solution
According to question, at $t = 0$, $A_0 = \frac{dN}{dt} = 1600$ C/s and at $t = 8$s, $A = 100$ C/s $\frac{A}{A_0} = \frac{1}{16}$ in 8s Therefore half life period, $t_{1/2} = 2$s $\therefore$ Activity at $t = 6$s $= 1600 \left(\frac{1}{2}\right)^3 = 200$ C/s
BETA
