Question

if refraction index of glass is 3/2 then what is the speed of light in glass ​

Answer 1

Answer:

Explanation: refractive index of de medium=speed of light in vaccuum/speed of light in given meium.

Answer 2

$\huge\mathfrak{Answer:}$

$\large\underline{\sf{\blue{Given:}}}$

• We have been given that refractive index of glass is 3/2
• Speed of light is 3 x 10^8

$\large\underline{\sf{\blue{To \: Find:}}}$

• We have to find the speed of light in glass from the above given information

$\large\underline{\sf{\blue{Concept \: Used:}}}$

Refractive Index :

• Refractive index of a material is a number that describes how fast the light travels through a medium

Formula :

$\boxed{\sf{\green{\mu \: (medium)= \dfrac{c}{v}}}}$

Where

$\boxed{\sf{c = Speed \: of \: light \: in \: vacuum}}$

$\boxed{\sf{v = Speed \: of \: light \: in \: given \: medium}}$

$\sf{}$

$\large\underline{\sf{\blue{Solution:}}}$

We have been given that Refractive Index of glass is 3/2

Let the speed of light in glass = s

$\sf{}$

$\large\underline{\mathfrak{\red{Using \: Refractive \: Index \: Formula :}}}$

$\implies \sf{\mu \: (glass) = \dfrac{c}{Speed \: in \: glass}}$

$\implies \sf{Speed \: in \: glass = \dfrac{3 \times 10^8}{ \mu }}$

$\implies \sf{Speed \: in \: glass = \dfrac{2 \times 3 \times 10^8}{3} }$

$\implies \sf{Speed \: in \: glass = \dfrac{2 \times \cancel{3}\times 10^8}{\cancel{3}}}$

$\implies \boxed{\sf{Speed \: in \: glass = 2 \times 10^8 \: m/s} }$

$\sf{}$

Hence Speed of light in glass is 2 x $\sf{10^8}$

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NOTE :

• Refractive Index below unity doesn't mean that light will travel faster than the speed of light in vaccum
• Studies also shows that Refractive Index of material can be negative which can occur if permittivity and permeability have simultaneous negative values

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