JEE Mains · Physics · STD 12 -6. Electromagnetic induction
A \(20\,cm\) long metallic rod is rotated with \(210\,rpm\) about an axis normal to the rod passing through its one end. The order end of the rod is in contact with a circular metallic ring. A constant and uniform magnetic field \(0.2\,T\) parallel to the axis exists everywhere. The emf developed between the centre and the ring is \(.......\,mV\).Take \(\pi=\frac{22}{7}\)
- A \(88\)
- B \(66\)
- C \(55\)
- D \(44\)
Answer & Solution
Correct Answer
(A) \(88\)
Step-by-step Solution
Detailed explanation
Here \(\omega=210\,rpm\) \(=210 \times \frac{2 \pi}{60}\,rad / s\) \(\Rightarrow \omega=7 \pi\,rad / s\) \(\ell=0.2\,w\) \(B =0.2\,T\) \(\text { emf developed across rod is }=\frac{1}{2} B \omega \ell^2\) \(\frac{1}{2} \times 0.2 \times 7 \pi \times(0.2)^2\) \(=88\,mV\)
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
- In an experiment to measure focal length \((f)\) of convex lens, the least counts of the measuring scales for the position of object \((u)\) and for the position of image \((v)\) are \(\Delta u\) and \(\Delta v\), respectively. The error in the measurement of the focal length of the convex lens will be _______.JEE Mains 2024 Hard
- The de Broglie wavelengths of a proton and an \(\alpha\) particle are \(\lambda\) and \(2 \lambda\) respectively. The ratio of the velocities of proton and \(\alpha\) particle will be _______.JEE Mains 2024 Hard
- The electric field at the point associated with a light wave is given by \(E=200\left[\sin \left(6 \times 10^{15}\right) t+\sin \left(9 \times 10^{15}\right) t\right] \,Vm ^{-1}\) Given : \(h=4.14 \times 10^{-15} \,eVs\) If this light falls on a metal surface having a work function of \(2.50 \,eV\), the maximum kinetic energy of the photoelectrons will be ........... \(eV\)JEE Mains 2022 Hard
- A solid disc of radius \(20 \,{cm}\) and mass \(10\, {kg}\) is rotating with an angular velocity of \(600\, {rpm}\), about an axis normal to its circular plane and passing through its centre of mass. The retarding torque required to bring the disc at rest in \(10\, {s}\, ......\, \pi \times \,10^{-1}\, {Nm}\).JEE Mains 2021 Medium
- An ideal gas has molecules with \(5\,\) degrees of freedom. The ratio of specific heats at constant pressure \((C_p)\) and at constant volume \((C_v)\) isJEE Mains 2017 Easy
- Two charges \(7 \mu \mathrm{c}\) and \(-4 \mu \mathrm{c}\) are placed at \((-7 \mathrm{~cm}, 0,0)\) and \((7 \mathrm{~cm}, 0,0)\) respectively. Given, \(\epsilon_0=8.85 \times 10^{-12} \mathrm{C}^2 \mathrm{~N}^{-1} \mathrm{~m}^{-2}\), the electrostatic potential energy of the charge configuration is :JEE Mains 2025 Medium
More PYQs from JEE Mains
- Given that \(1\,g\) of water in liquid phase has volume \(1\,cm^3\) and in vapour phase \(1671\, cm^3\) at atmospheric pressure and the latent heat of vaporization of water is \(2256\,J/g;\) the change in the internal energy in joules for \(1\,g\) of water at \(373\,K\) when it changes from liquid phase to vapour phase at the same temperature is ....... \(J\)JEE Mains 2019 Medium
- Let \(\mathrm{a}, \mathrm{b} \in R, \mathrm{b} \neq 0\), Define a function \(f(x)= \begin{cases}\operatorname{a} \sin \frac{\pi}{2}(x-1), & \text { for } x \leq 0 \\ \frac{\tan 2 x-\sin 2 x}{b x^{3}}, & \text { for } x>0\end{cases}\) If \(f\) is continuous at \(x=0\), then \(10-a b\) is equal to ...... .JEE Mains 2021 Medium
- The energy levels of an hydrogen atom are shown below. The transition corresponding to emission of shortest wavelength is
JEE Mains 2023 Medium - If \(^n{C_4},{\,^n}{C_5},\) and \({\,^n}{C_6},\) are in \(A.P.,\) then \(n\) can beJEE Mains 2019 Hard
- Words with or without meaning are to be formed using all the letters of the word \(EXAMINATION.\) The probability that the letter \(\mathrm{M}\) appears at the fourth position in any such word is:JEE Mains 2021 Hard
- Three infinitely long charged thin sheets are placed as shown in figure. The magnitude of electric field at the point \(P\) is \(\frac{x \sigma}{\epsilon_0}\). The value of \(x\) is _______. (all quantities are measured in \(SI\) units).
JEE Mains 2024 Hard