Student Login

Home›Chapters›Nuclear Physics PYQs›Law of Radioactive Decay›Question 77

JEE Main 2020 (5 Sep, Shift 1) · Law of Radioactive Decay

Law of Radioactive Decay question from JEE Main 2020 (5 Sep, Shift 1)

Q77JEE Main 2020 · 5 SEP · SHIFT 1Medium

Law of Radioactive Decay

Activities of three radioactive substances A, B and C are represented by the curves A, B and C, in the figure. Then their half-lives

$T_{\frac{1}{2}}(A)$ : $T_{\frac{1}{2}}(B)$ : $T_{\frac{1}{2}}(C)$ are in the ratio:

Show answer and solution

Answer: (d)

$R = R_0 e^{-\lambda t} \Rightarrow \ln R = \ln R_0 - \lambda t$ , so $\lambda$ = magnitude of slope.
$\lambda_A = 6/10 = 0.6$ , $\lambda_B = 6/5 = 1.2$ , $\lambda_C = 2/5 = 0.4$ per year.
$T_{1/2} \propto \frac{1}{\lambda}$ : $\frac{1}{0.6} : \frac{1}{1.2} : \frac{1}{0.4} = 2 : 1 : 3$ .
So the answer is (d) 2 : 1 : 3.

Report a mistake

More questions on Law of Radioactive Decay

The rate of radioactive disintegration at an instant for a radioactive sample of half…NEET 2019
Using a nuclear counter the count rate of emitted particles from a radioactive source is…JEE Main 2019 (10 Jan, Shift 1)
Half lives of two radioactive nuclei A and B are 10 minutes and 20 minutes, respectively…JEE Main 2019 (12 Apr, Shift 2)
Two radioactive substances A and B have decay constants 5 λ and λ respectively. At t = 0…JEE Main 2019 (10 Apr, Shift 2)
Two radioactive materials A and B have decay constants 10 λ and λ, respectively. It…JEE Main 2019 (10 Apr, Shift 1)
A sample of radioactive material A, that has an activity of 10 mCi(1 Ci = 3.7 × 1010…JEE Main 2019 (9 Jan, Shift 1)
At a given instant, say t = 0, two radioactive substance A and B have equal activities…JEE Main 2019 (9 Jan, Shift 2)
For a radioactive material, half-life is 10 minutes. If initially there are 600 number of…NEET 2018