A 20cm long metallic rod is rotated with 210rpm about an axis...

A $20cm$ long metallic rod is rotated with $210rpm$ about an axis normal to the rod passing through its one end. The other end of the rod is in contact with a circular metallic ring. A constant and uniform magnetic field $0 . 2T$ parallel to the axis exists everywhere. The emf developed between the centre and the ring is _________ $mV$ .

(Take $\pi = \dfrac{22}{7}$ )

Correct answer

Step-by-step solution

The data given is
$\omega = 210 \times \dfrac{2\pi}{60}rad{s}^{- 1} = 7\pi rad{s}^{- 1}l = 0 . 2mB = 0 . 2T$
The emf is given by
$ε = \dfrac{B\omega{l}^{2}}{2}$
$= 0 . 2 \times 7\pi \times \dfrac{{\left(0 . 2\right)}^{2}}{2}$
$= 88mV$

Practice Electromagnetic Induction on Quantrex Academy →

More from Electromagnetic Induction

List-I contains four conducting loops lying in the XY plane, as shown in the figures. The… JEE Advanced 2026 A 30 cm long solenoid has 10 turns per cm and area of 5 cm ^2 . The current through the… JEE Main 2026 A square loop of side 2 cm is placed in a time varying magnetic field with magnitude as B… JEE Main 2026 An inductor of inductance 10 mH having resistance of 100\,Ω is connected to battery of… JEE Main 2026 A metal rod of length L rotates about one end at origin with a uniform angular velocity ω… JEE Main 2026 A circular loop of radius 20 cm and resistance 2\ Ω is placed in a time varying magnetic… JEE Main 2026 In the given circuit below inductance values of L_1 , L_2 and L_3 are same. The magnetic… JEE Main 2026 A circular current loop of radius R is placed inside square loop of side length L (L >>… JEE Main 2026 Full Electromagnetic Induction list All JEE Main PYQs