RE-NEET2026Physics-Electromagnetic Waves

RE-NEET 2026 Physics Wave Propagation MCQ Question

Type: MCQ-conceptual-Medium-Class 12

An electromagnetic wave travelling in a lossless dielectric medium having a dielectric constant, εᵣ=9, has the electric field, Eₓ=E₀sin (kz2z^{-2}π×10⁶t) Vm⁻¹ where E₀ is the amplitude and k is the wave vector. Among the following options, the incorrect choice is:

A

The wavelength of the electromagnetic wave inside the medium is 300 m

B

The magnetic field is given by the relation Bᵧ = B₀/ν sin (kz2z^{-2}π×10⁶t) where ν is the speed of the electromagnetic wave inside the medium

C

The direction of propagation of the electromagnetic wave is along +z

D

The speed of the electromagnetic wave inside the medium is 10⁸ ms⁻¹

Correct Answer

Option D

Detailed Explanation

The speed of the wave in the medium is c/√εᵣ = 3×10⁸/3 = 10⁸ m/s, which is correct, but the option states it incorrectly.

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