JEE Main 2026 · 4 Apr · Shift 2 · Physics Q40

← JEE Main 2026 · 4 Apr · Shift 2

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A magnetic field vector in an electromagnetic wave is represented by $\vec B=B_0\sin\left(2\pi\nu t-\dfrac{2\pi x}\lambda\right)\hat j$ . Its associated electric field vector is ________.

\vec E=-\nu\lambda B_0\sin\left(2\pi\nu t-\dfrac{2\pi x}\lambda\right)\hat k

\vec E=-\nu\lambda B_0\sin\left(2\pi\nu t-\dfrac{2\pi x}\lambda\right)\hat i

\vec E=\nu\lambda B_0\sin\left(2\pi\nu t-\dfrac{2\pi x}\lambda\right)\hat k

\vec E=\nu\lambda B_0\sin\left(2\pi\nu t-\dfrac{2\pi x}\lambda\right)\hat i

Answer and worked solution

Official answer: A

Magnitude. $E_0=cB_0=\nu\lambda B_0$ .

Direction. $\vec E\times\vec B$ must point along $+\hat x$ (the direction of travel). With $\vec B\parallel\hat j$ : $(-\hat k)\times\hat j=\hat i$ , so $\vec E$ is along $-\hat k$ .

(A)

Topics:Properties of EM waves

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JEE Main 2026 · 4 Apr · Shift 2, Physics question 40