JEE Mains · Physics · STD 12 - Nuclei
- JEE Mains 2022
- Medium
- MCQ
The disintegration rate of a certain radioactive sample at any instant is \(4250\) disintegrations per minute.\(10\) minutes later, the rate becomes \(2250\) disintegrations per minute. The approximate decay cons \(.........\min^{-1}\)
Pick an option to check your answer.
Answer & Solution
Correct Answer
(C) \(0.063\)
Step-by-step Solution
Detailed explanation
At \(t=0\) disintegration rate \(=4250\,dpm\)
At \(t=10\) disintegration rate \(=2250\,dpm\)
\(A=A_{0} e^{-\lambda t}\)
\(2250=4250\,e ^{-\lambda .(10)}\)
\(\Rightarrow \lambda(10)=\ln \left(\frac{4250}{2250}\right)\)
\(\Rightarrow \lambda=0.063 min ^{-1}\)
More questions from Physics
- A mixture of carbon dioxide and oxygen has volume \(8310\) cm\(^3\), temperature \(300\) K, pressure \(100\) kPa and mass \(13.2\) g. The number of moles of carbon dioxide and oxygen gases in the mixture respectively are _______.
(Assume both carbon dioxide and oxygen gases behave like ideal gases) \([R = 8.31\) J/mol.K\(]\)JEE Mains 2026 Hard - At time \(t =0\) a particle starts travelling from a height \(7\,\hat{z} cm\) in a plane keeping \(z\) coordinate constant. At any instant of time it's position along the \(x\) and \(y\) directions are defined as \(3\,t\) and \(5\,t^{3}\) respectively. At \(t =1\,s\) acceleration of the particle will be.JEE Mains 2022 Medium
- A cylinder with fixed capacity of \(67.2\, lit\) contains helium gas at \(STP\). The amount of heat needed to raise the temperature of the gas by \(20\,^oC\) is ..... \(J\) [Given that \(R = 8.31\, J\, mol^{-1}\, K^{-1}\)]JEE Mains 2019 Medium
- A Young's doublc\(-\)slit experiment is performed using monochromatic light of wavelength \(\lambda\). The intensity of light at a point on the screen, where the path difference is \(\lambda,\) is \(K\) units. The intensity of light at a point where the path difference is A \(\frac{\lambda}{6}\) is given by \(\frac{n K}{12},\) where \(n\) is an integer. The value of \(n\) is\(......\)JEE Mains 2020 Medium
- A \(72 \; \Omega\) galvanometer is shunted by a resistance of \(8 \; \Omega\). The percentage of the total current which passes through the galvanometer is \(.....\)JEE Mains 2022 Medium
- A heating element has a resistance of \(100\,\Omega \) at room temperature. When it is connected to a supply of \(220\,V,\) a steady current of \(2\,A\) passes in it and temperature is \(500\,^oC\) more than room temperature. What is the temperature coefficient resistance of the heating element?JEE Mains 2018 Hard
More PYQs from JEE Mains
- A wire having a linear mass density \(9.0 \times 10^{-4} \;{kg} / {m}\) is stretched between two rigid supports with a tension of \(900\; {N}\). The wire resonates at a frequency of \(500\;{Hz}\). The next higher frequency at which the same wire resonates is \(550\; {Hz}\). The length of the wire is \(...... {m}\)JEE Mains 2021 Hard
- A convex lens of focal length 30 cm is placed in contact with a concave lens of focal length 20 cm. An object is placed at 20 cm to the left of this lens system. The distance of the image from the lens in cm is ________JEE Mains 2025 Easy
- In the figure shown, after the switch \(‘S’\) is turned from position \(‘A’\) to position \(‘B’\), the energy dissipated in the circuit in terms of capacitance \(‘C’\) and total charge \(‘Q’\) is
JEE Mains 2019 Hard - in circular plate of mass \(M\) and radius \(R\) has its density varying as \(p\left( r \right) = {p_0}\,r\) with \(P_0\) as constant and \(r\) is the distance from its center. The moment of Inertia of the circular plate about an axis perpendicular to the plate and passing through its edge is \(I = aMR^2\) . The value of the coefficient \(a\) isJEE Mains 2019 Hard