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As shown in the figure, after passing through the medium 1, the speed of light v₂ in medium 2 will be (Given c = 3 × 10⁸ m s⁻¹

Asked in JEE Main 28th July 1st Shift 2022 · Speed in vacuum and in a medium

• (1) 1.0 × 10⁸ m s⁻¹
• (2) 0.5 × 10⁸ m s⁻¹
• (3) 1.5 × 10⁸ m s⁻¹
• (4) 3.0 × 10⁸ m s⁻¹

Step-by-step solution

Why the other options are wrong

• (2) 0.5 × 10⁸ divides c by n₁n₂ = 2 × 3 = 6; the slabs do not compound
• (3) 1.5 × 10⁸ is v₁, the speed inside medium 1 (n₁ = √4 = 2)
• (4) 3.0 × 10⁸ is the speed in air; the wave does slow down inside medium 2

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