A plane electromagnetic wave has electric field $\vec{E}_{z}$ =100 cos(6×10⁸t+4x) k̂ V/m and propagates in a non-magnetic medium. Find the dielectric constant of the medium.
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Question

A plane electromagnetic wave has electric field E ⃗ z \vec{E}_{z} E z ​ =100 cos(6×10⁸t+4x) k̂ V/m and propagates in a non-magnetic medium. Find the dielectric constant of the medium.

G1 Physics · Accepted Answer

For the z-directed electric field E⃗=100cos(6×10⁸t+4x) k̂ V m⁻¹, ω=6×10⁸ rad s⁻¹ and k=4 m⁻¹. Thus v=ω/k=1.5×10⁸ m s⁻¹. For a non-magnetic medium v=c/√εᵣ, so εᵣ=(c/v)²=4. Option D.

A plane electromagnetic wave has electric field E ⃗ z \vec{E}_{z} E z ​ =100 cos(6×10⁸t+4x) k̂ V/m and propagates in a non-magnetic medium. Find the dielectric constant of the medium.

A plane electromagnetic wave has electric field E ⃗ z \vec{E}_{z} E z =100 cos(6×10⁸t+4x) k̂ V/m and propagates in a non-magnetic medium. Find the dielectric constant of the medium.