A magnetic field vector in an electromagnetic wave is represented by B = B₀sin (2πν t - (2π x)/(λ))j. Its associated electric field vector is ______. (a) E = -νλ B₀sin (2πν t - (2π x)/(λ))k (b) E = -νλ B₀sin (2πν t - (2π x)/(λ))i (c) E = νλ B₀sin (2πν t - (2π x)/(λ))k (d) E = νλ B₀sin (2πν t - (2π x)/(λ))i

Answer: (a). Phase (ω t - kx): wave moves along +x; E₀ = cB₀ = νλ B₀. Need E× j = + i: (- k)× j = i, so E is along - k. So the answer is (a) E = -νλ B₀sin (2πν t - 2π x/λ) k.

A magnetic field vector in an electromagnetic wave is represented by… | JEE Main 2026 (4 Apr, Shift 2)

Q3JEE Main 2026 · 4 APR · SHIFT 2Medium

Nature of EM Waves & Wave Equation

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

Show answer and solution

Answer: (a)

Phase $(\omega t - kx)$ : wave moves along $+x$ ; $E_0 = cB_0 = \nu\lambda B_0$ .
Need $\hat E\times\hat j = +\hat i$ : $(-\hat k)\times\hat j = \hat i$ , so $\vec E$ is along $-\hat k$ .
So the answer is (a) $\vec E = -\nu\lambda B_0\sin(2\pi\nu t - 2\pi x/\lambda)\hat k$ .

Report a mistake

Nature of EM Waves & Wave Equation question from JEE Main 2026 (4 Apr, Shift 2)

More questions on Nature of EM Waves & Wave Equation