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| Verification of Snell's Law |
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 Place a rectangular glass slab on a white sheet of paper fixed on a drawing board. |
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 Trace the boundary ABCD of the glass slab. |
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 Remove the glass slab and draw a normal N1N2 at O. |
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 Draw a straight line IO inclined at an angle say 30o with the normal. IO is the incident ray. |
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 Fix two pins P and Q on the incident ray IO. |
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 Place the glass slab within its boundary ABCD. |
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 Looking from the other side of the glass slab fix two other pins R and S such that P, Q, R and S appear to lie on the same straight line. |
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 Remove the glass slab and the pins. Mark the pin points P, Q, R and S. |
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 Join the pins R and S and produce the line on both sides. The ray O1E is the emergent ray. |
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 Join OO1. It is the refracted ray. |
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 With O as centre, draw a circle of a convenient radius 'r' in such a way that it cuts the incident and the refracted rays at F and G respectively. |
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 From F and G draw perpendiculars to the normal N1N2. |
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 DFHO and DGKO are right angled triangles. |
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| But OG = OF = r |
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 Measure the length of FH and GK. |
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 Repeat the experiment for different values of angle of incidence. |
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 Record the result in tabular form |
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