Electromagnetic Waves

JEE Main level, single correct, medium

60 of 165

Question 60 of 165

The oscillating magnetic field in a plane electromagnetic wave is given by By=5×10−6sin⁡1000π(5x−4×108t)T{B}_{y}=5\times {10}^{-6}\sin 1000\pi \left(5x-4\times {10}^{8}t\right)T. The amplitude of electric field will be

Show answer and solution

Answer: (D) 4×102Vm−14\times {10}^{2}{Vm}^{-1}

Given here, By=5×10−6sin⁡1000π(5x−4×108t)T{B}_{y}=5\times {10}^{-6}\sin 1000\pi \left(5x-4\times {10}^{8}t\right)T
Here, peak value of magnetic field, B0=5×10−6T{B}_{0}=5\times {10}^{-6}T
Now the speed of the wave v=ωk=1000π×4×1081000π×5=8×107ms−1v=\dfrac{\omega }{k}=\dfrac{1000\pi \times 4\times {10}^{8}}{1000\pi \times 5}=8\times {10}^{7}m{s}^{-1}
Using relation between magnetic and electric field,
Peak value of electric field is E0=B0v=5×10−6×8×107=4×102Vm−1{E}_{0}={B}_{0}v=5\times {10}^{-6}\times 8\times {10}^{7}=4\times {10}^{2}V{m}^{-1}

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.

More Physics practice

JEE Main Physics practice question on Electromagnetic Waves (Electromagnetic Waves and Maxwell's equations), with the answer and a step-by-step solution. Scan a question from your own book or paper to get a whiteboard video.