A uniform place wave in air impinges at 45º angle on a

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A uniform place wave in air impinges at 45º angle on a lossless dielectric material with dielectric constant ∈_r. The transmitted wave propagate in a 30º direction with respect to the normal the wave of ∈_r is—

1. 1.5
2. √1.5
3. 2
4. √2

Correct Option: C

From Snell’s law
n₁ sin θ₁ = n₂ sin θ₂
n₁ = √ε₀ (free space or air)
n₂ = √ε_rε₀
θ₁ → incident angle with normal
θ₂ → transmitted angle with normal
ε₀ sin (45°) = √ε_rε₀ sin 30°

⇒	√ε₀	=	√ε_rε₀	√ε_r = √2 ⇒ ε_r = 2
	√2		2