QQuestion
Determine the speed of a light ray passing through a glass slab of refractive index 1.5. [c = 3 × 10⁵ m s⁻¹]
✓Answer
Refractive index of glass (μ) = 1.5
Speed of light in vacuum (c) = 3 × 10⁵ m s⁻¹
Speed of light in glass (v) = ?
We know, μ = \frac{\text{c}}{\text{v}}
Therefore,
v = \frac{\text{c}}{\text{μ}}
= \frac{3\times10^5}{1.5}
= 2 × 10⁵ m s⁻¹
Hence, the speed of light in the glass slab is 2 × 10⁵ m s⁻¹.
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