Electromagnetic Induction

JEE Main level, numerical answer, medium

71 of 153

Question 71 of 153

A conducting circular loop is rotated about its diameter at a constant angular speed of 100rad/s100 \mathrm{rad} / \mathrm{s} in a magnetic field of 0.5 T perpendicular to the axis of rotation. When the loop is rotated by 30∘30^{\circ} from the horizontal position, the induced EMF is 15.4 mV. The radius of the loop is ____\_\_\_\_ mm. (Take π=227\pi=\frac{22}{7})

Show answer and solution

Answer: 14

E=BωAsin⁡ωtE = B\omega A \sin\omega t
15.4×10−3=12×100×227r2×1215.4 \times 10^{-3} = \dfrac{1}{2} \times 100 \times \dfrac{22}{7} r^2 \times \dfrac{1}{2}
r=15.4×28×10−522r = \sqrt{\dfrac{15.4 \times 28 \times 10^{-5}}{22}}
R=14 mmR = 14 \text{ mm}

JEE Main question paper PDF

Open a shift to read the full paper on this page, or download it.

JEE Main 2025 Apr 2 Shift 1 question paper

Open Download PDF

Opening paper…

Explain it as a whiteboard videoStep-by-step, in Hinglish or English. Your first video needs no login.Solved it on paper but got it wrong?Upload a photo of your working. Mistake Doctor marks the exact line that broke.
See it move: Electromagnetic induction simulationDrag the sliders and watch the numbers in this question change.

More Physics practice

JEE Main Physics practice question on Electromagnetic Induction (Motional and Rotational EMF), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.