Physics, asked by rrogermel, 1 year ago

If refractive index of glass is 1.65 what is the speed of light in glass

Answers

Answered by yash1273
8
Light travels at approximately 300,000 kilometers per second in a vacuum, which has a refractive index of 1.0, but it slows down to 225,000 kilometers per second in water (refractive index = 1.3) and 200,000 kilometers per second in glass (refractive index of 1.5).

rrogermel: Thanks a lot dude
swetapshah91: Worst answer who made youexpert and you get it from some website
Answered by Anonymous
11

 \Large \bf Given :

 \bf Refractive \: index \: of \: flint \: glass, \: η_{g} = 1.65

 \Large \bf To \: Find :

 \bf Speed \: of \: light \:  in \:  glass, v_{g}

 \Large \bf Solution :

 \bf We \: know \:  that \: speed \: of \: light \: in \: air, c=3×10⁸m/s

Now, by formula :

 \bf η_{g} = \dfrac{c}{v_{g}}

 \bf \implies v_{g} = \dfrac{c}{η_{g}}

 \bf \implies v_{g} = \dfrac{3 \times 10^{8}m/s}{1.65}

 \bf \implies v_{g} = \dfrac{3}{1.65}\times 10^{8}m/s

 \bf \implies v_{g} = \dfrac{3 \times 100}{165}\times 10^{8}m/s

 \bf \implies v_{g} = \dfrac{\cancel{3} \times 100}{\times{\cancel{165}}_{55}}\times 10^{8}m/s

 \bf \implies v_{g} = \dfrac{100}{55}\times 10^{8}m/s

 \bf \implies v_{g} = 1.8181... \times 10^{8}m/s

 \bf \implies v_{g} = 1.82 \times 10^{8}m/s \: (approx.)

 \bf \therefore Speed \: of \: light \:  in \:  glass, v_{g} =  1.82 \times 10^{8}m/s \: (approx.)

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