An EM wave propagating in x-direction has a wavelength of 8 mm. The electric field vibrating y- direction has maximum magnitude of 60 Vm ⁻¹. Choose the correct equations for electric and magnetic fields if the EM wave is propagating in vacuum: (a) Ey = 60sin [π/4× 10³(x - 3× 10⁸t)]j V m⁻¹ Bz = 2sin [π/4× 10³(x - 3× 10⁸t)]k T (b) Ey = 60sin [π/4× 10³(x - 3× 10⁸t)]j V m⁻¹ Bz = 2× 10⁻⁷sin [π/4× 10³(x - 3× 10⁸t)]k T (c) Ey = 2× 10⁻⁷sin [π/4× 10³(x - 3× 10⁸t)]j V m⁻¹ Bz = 60sin [π/4× 10³(x - 3× 10⁸t)]k T (d) Ey = 2× 10⁻⁷sin [π/4× 10⁴(x - 4× 10⁸t)]j V m⁻¹ Bz = 60sin [π/4× 10⁴(x - 4× 10⁸t)]k T

Answer: (b). k = 2π8×10⁻³ = π/4×10³ m ⁻¹, wave speed 3×10⁸ m/s. B₀ = 603×10⁸ = 2×10⁻⁷ T along z (since y× z = x). So the answer is (b).

An EM wave propagating in x-direction has a wavelength of 8 mm. The… | JEE Main 2022 (28 Jun, Shift 2)

Q38JEE Main 2022 · 28 JUN · SHIFT 2Medium

Nature of EM Waves & Wave Equation

An EM wave propagating in x-direction has a wavelength of 8 mm. The electric field vibrating y- direction has maximum magnitude of 60 Vm ${}^{-1}$ . Choose the correct equations for electric and magnetic fields if the EM wave is propagating in vacuum:

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Answer: (b)

$k = \dfrac{2\pi}{8\times10^{-3}} = \dfrac{\pi}{4}\times10^{3}$ m $^{-1}$ , wave speed $3\times10^{8}$ m/s.
$B_0 = \dfrac{60}{3\times10^{8}} = 2\times10^{-7}$ T along $z$ (since $\hat y\times\hat z = \hat x$ ).
So the answer is (b).

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Nature of EM Waves & Wave Equation question from JEE Main 2022 (28 Jun, Shift 2)

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