NEET 2022 · PhysicsSpeed in mediumPrevious Year Question
When light propagates through a material medium of relative permittivity ε_r and relative permeability µ_r, the velocity of light v is given by (c = velocity of light in vacuum)
Answer: (D) v = c / √(µ_r ε_r). Answer: (D) v = c / √(µ_r ε_r).
- A.v = c
- B.v = c × √(µ_r ε_r)
- C.v = √(ε_r / µ_r)
- D.v = c / √(µ_r ε_r)✓
Correct Answer
(D) v = c / √(µ_r ε_r)
Solution & Explanation
Answer: (D) v = c / √(µ_r ε_r). The speed in a medium is v = 1/√(µε) = 1/√(µ₀µ_r ε₀ε_r) = c/√(µ_r ε_r), since c = 1/√(µ₀ε₀).
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