Electromagnetic Waves

JEE Main level, single correct, medium

100 of 165

Question 100 of 165

If the magnetic field in a plane electromagnetic wave is given by B⃗=3×10−8sin⁡⁡(1.6×103x+48×1010t)j^T,\vec{B}=3\times {10}^{-8}\sin ⁡\left(1.6\times {10}^{3}x+48\times {10}^{10}t\right)\hat{j}T, then what will be expression for electric field ?

Show answer and solution

Answer: (B) E⃗=(9sin⁡⁡(1.6×103x+48×1010t)k^Vm)\vec{E}=\left(9\sin ⁡\left(1.6\times {10}^{3}x+48\times {10}^{10}t\right)\hat{k}\dfrac{V}{m}\right)

E0B0=C\dfrac{{E}_{0}}{{B}_{0}}=C (speed of light in vacuum)
E0=B0C=3×10−8×3×108{E}_{0}={B}_{0}C=3\times {10}^{-8}\times 3\times {10}^{8}
=9NC=9\dfrac{N}{C}
So,

E=9sin⁡⁡(ωt+kx+ϕ)E=9\sin ⁡\left(\omega t+kx+\phi \right)
E⃗=(9sin⁡⁡(1.6×103x+48×1010t)k^Vm)\vec{E}=\left(9\sin ⁡\left(1.6\times {10}^{3}x+48\times {10}^{10}t\right)\hat{k}\dfrac{V}{m}\right)

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