Light travels with a velocity 1.5 × 108 m/s in a medium. On entering

1.	Light travels with a velocity 1.5 × 108 m/s in a medium. On entering second medium its velocity becomes 0.75 × 108 m/s. What is the refractive index of the second medium with respect to the first medium?(c = 3 × 108 m/s)
Answer» Given: Velocity of light in the first medium = v₁ = 1.5 × 10⁸ m/s, velocity of light in the second medium = v₂ = 0.75 × 10⁸ m/s, refractive index of the second medium with respect to the first medium = ₂n₁ = ? ₂n₁ = \(\frac{v_1}{v_2}\) ₂n₁ = \(\frac{1.5\times10^8}{0.75\times10^8}\) = 2 Hence, the refractive index of the second medium with respect to the first medium is 2. [Note : The absolute refractive index of the second medium = \(\frac{3\times10^8m/s}{0.75\times10^8m/s}\) = 4 (greater than that of diamond, not likely).]

Light travels with a velocity 1.5 × 108 m/s in a medium. On entering second medium its velocity becomes 0.75 × 108 m/s. What is the refractive index of the second medium with respect to the first medium?(c = 3 × 108 m/s)

Answer»

Given: Velocity of light in the first medium = v₁ = 1.5 × 10⁸ m/s,

velocity of light in the second medium = v₂ = 0.75 × 10⁸ m/s,

refractive index of the second medium with respect to the first medium = ₂n₁ = ?

₂n₁ = \(\frac{v_1}{v_2}\)

₂n₁ = \(\frac{1.5\times10^8}{0.75\times10^8}\) = 2

Hence, the refractive index of the second medium with respect to the first medium is 2.

[Note : The absolute refractive index of the second medium = \(\frac{3\times10^8m/s}{0.75\times10^8m/s}\) = 4

(greater than that of diamond, not likely).]