Find Group Velocity in Glass: Optics Problems

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The discussion focuses on calculating the group velocity in glass with a dispersive power of 1/30 and an index of refraction (nd) of 1.5. The relevant equation for group velocity is Vg = Vp(1 - (k/n)(dn/dλ)), where n(λ) = 1.5255 + (4825)/λ provides the necessary refractive index values. Additionally, the formation of interference fringes in a soap film illuminated by laser light at 632.8nm is addressed, emphasizing the localized patterns observed due to constructive and destructive interference.

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  • Understanding of optical dispersion and refractive indices
  • Familiarity with the concept of group velocity in wave mechanics
  • Knowledge of interference patterns in optics
  • Basic proficiency in calculus for differentiation (dn/dλ)
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  • Study the derivation of the group velocity formula in optics
  • Explore the principles of optical interference and fringe formation
  • Investigate the application of the equation n(λ) = 1.5255 + (4825)/λ in various optical materials
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1. The dispersive power of glass is defined as the ratio(nf-nc)/(nd-1) where c, d and f are the frauhofer wavelengths. Find the approximate group velocity in glass whose dispersive power is 1/30 and nd =1.5

2. A soap film is formed suing a rectangular wire frame and held in a vertial plane. When illuminated normally by laser light at 632.8nm, one sees a series of localized interference fringes that measure15 per cm. Explain their formation.

Ok so for 1, there is a n equation for another problem that is ued to calculate all the n-values, but I'm not sure if its used in all cases or just in that problem. It is n([tex]\lambda[/tex]) = 1.5255 + (4825)/[tex]\lambda[/tex]. Also don't really know how these numbers relate to calculating the group velocity if its Vg = Vp(1-(k/n)(dn/d[tex]\lambda[/tex]))

As for 2, I really don't have any idea. Don't know where to start. Wouldn't mind a wee nudge in the right direction.
 
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