COMEDK · Physics · 29. Nuclear Physics
Two radioactive materials \(X_{1}\) and \(X_{2}\) have decay constant \(5 \lambda\) and \(\lambda\), respectively. If initially they have the same number of nuclei, then the ratio of the number of nuclei of \(X_{1}\) to that \(X_{2}\) will be \(1 / e\) after a time
- A \(1 / 4 \lambda\)
- B \(e / \lambda\)
- C \(\lambda\)
- D \(\frac{1}{2} \lambda\)
Answer & Solution
Correct Answer
(A) \(1 / 4 \lambda\)
Step-by-step Solution
Detailed explanation
Decays constants of radioactive materials \(X_{1}\) and \(X_{2}\) is given as \(\lambda_{1}=5 \lambda\) and \(\lambda_{2}=\lambda\) If \(N_{0}\) be the initial number of nuclei in both radioactive materials, then according to radioactive decay law,…
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- An iron piece of mass \(200 \mathrm{~g}\) is kept inside a furnace for some time and then put in a calorimeter of water equivalent \(20 \mathrm{~g}\) containing \(230 \mathrm{~g}\) of water at \(20 \mathrm{C}\). The steady state temperature attained by the mixture is \(60^{\circ}\). The temperature of the furnace is (Specific heat capacity of iron is \(470 \mathrm{~J~kg}^{-1} \mathrm{C}^{-1}\) )COMEDK 2024 Medium
- The dimension \([\mathrm{ML}^{-1} \mathrm{~T}^{-2}]\) is the physical quantity ofCOMEDK 2024 Easy
- If kinetic energy of a body is increased by \(300 \%\), then percentage change in momentum will beCOMEDK 2022 Medium
- Electron of mass \(m\) and charge \(q\) is travelling with a speed \(v\) along a circular path of radius \(r\) at right angles to a uniform magnetic field of intensity \(B\). If the speed of the electron is doubled and the magnetic field is halved, then the resulting path would have a radiusCOMEDK 2017 Easy
- The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than \(1.24 \mu \mathrm{~m}\) is incident on it. The band gap (in eV ) for the semiconductor isCOMEDK 2025 Medium
- Two coherent monochromatic light beams of intensities \(I\) and \(4 I\) are superimposed. The maximum and minimum possible resulting intensities areCOMEDK 2015 Easy
More PYQs from COMEDK
- An electric current \(I\) enters and leaves a uniform circular wire of radius \(r\) through diametrically opposite points. A charged particle \(q\) moves along the axis of circular wire passes through its centre with speed \(v\). The magnetic force on the particle when it passes through the centre has a magnitudeCOMEDK 2022 Hard
- The temperature at which centigrade and Fahrenheit scales give the same reading, isCOMEDK 2015 Easy
- \(\text { If } x^2+y^2=t+\dfrac{1}{t} \text { and } x^4+y^4=t^2+\dfrac{1}{t^2} \text { then } \dfrac{d y}{d x}=\)COMEDK 2024 Medium
- A constant current flows from \(A\) to \(B\) as shown in the figure. What is the direction of current in the circle?
COMEDK 2021 Hard - The amplitude of \((1+i)^{5}\) isCOMEDK 2020 Easy
- The value of \(c\) in Lagrange's mean value theorem for the function \(f(x)=\log (\sin x)\) in the interval \(\left[\frac{\pi}{6}, \frac{5 \pi}{6}\right]\) isCOMEDK 2015 Easy