Practice portal › Ray Optics and Optical Instruments › Refraction and Total Internal Reflection
Asked in GSEB Board July 2023 · Snell's law, slabs and apparent depth
Given: n = 1.53 for the glass and c = 3×10⁸ m s⁻¹.
Idea: the refractive index is defined as n = c/v, so v = c/n: light is slower in the medium, by the factor n.
v = (3×10⁸)/(1.53)
v = 1.96×10⁸ m/s.
Quick size check: n is a little over 1.5, so the answer should be a little under two thirds of c, and it is.
So light travels through this glass at 1.96×10⁸ m/s.
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