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yglo98

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- Homework Statement
- Want help with physics question from my book.

- Relevant Equations
- My idea for 1. is to use the formula for refraction in spherical surfaces: (n1/2) + (n2/s') = (n2-n1)/R), where n is refraction index for glass and air. First I would apply it for the first front surface of the glass, then take the image of that and use it as the object for the second refraction in the back side. I would have to take into account for the sign convention and thickness of the lens.

For 2 I think that maybe we can approximate the 2 refractions as right angles and then use the formula: T=(1-R)*2, where the (initial intensity/transmitted intensity) = T, and R=(n1-n2)^2/(n1+n2)^2. It would be used two times, as in the 2 refractions. But exactly how I would write the intensity, effect and area in the right way to solve this I don't know.

A red laser with the diameter of 3mm is directed towards a piece of glass. It has the effect, P of 1mW. The angle of incidence is 90 degrees. The glass has refraction index n2= 1,5 and thickness 2 cm. Its front side is convex with a convergence radius,R, of 11 cm. The back side is plane.

- Whats the distance between the focal point and the back side of the glass?
- What effect is being focused in the focal point?

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