JEE PYQ: Nuclear Physics Question 1
Question 1 - 2021 (16 Mar Shift 2)
The half-life of $\text{Au}^{198}$ is 2.7 days. The activity of 1.50 mg of $\text{Au}^{198}$ if its atomic weight is 198 g mol$^{-1}$ is. ($N_A = 6 \times 10^{23}$/mol)
(1) 240 Ci
(2) 357 Ci
(3) 535 Ci
(4) 252 Ci
Show Answer
Answer: (2)
Solution
$A = \lambda N$, $N = nN_A$ $N = \left(\frac{1.5 \times 10^{-3}}{198}\right) N_A$ $A = \left(\frac{\ln 2}{t_{1/2}}\right) N$ 1 Curie $= 3.7 \times 10^{10}$ Bq $A = 365$ Bq $\approx 357$ Ci
BETA
