What is the phase velocity of light in glass?

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SUMMARY

The phase velocity of light in glass with a refractive index (n) of 1.5 is calculated using the formula vp = c/n, where c is the speed of light in vacuum (3x10^8 m/s). The calculation yields a phase velocity (vp) of 2x10^8 m/s. The wavelength (λ) of 500nm is not needed for this specific calculation, as the refractive index is sufficient to determine the phase velocity. This confirms that while n can vary with wavelength, it does not affect the calculation in this instance.

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  • Understanding of refractive index and its significance in optics
  • Familiarity with the speed of light in vacuum (c = 3x10^8 m/s)
  • Basic knowledge of phase velocity and its relation to wavelength
  • Ability to manipulate algebraic equations for solving physics problems
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  • Study the relationship between refractive index and wavelength in different materials
  • Explore the concept of group velocity in optical media
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ZedCar
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Homework Statement



What is the phase velocity of light in glass if n=1.5 at λ=500nm

Homework Equations



n=c/vp =λ0/λ


The Attempt at a Solution



1.5 = (3x10^8) / vp
vp = (3x10^8)/1.5

I'm not entirely sure if the equation I have used is the correct one. It does not use the λ=500nm as given in the question.
 
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It is right, and you do not need the wavelength. In general, n will depend on the wavelength, but that is not relevant here.
 
Thanks mfb!
 

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