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In this problem, a layer of water covers an unknown material x.
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A light ray travelling upward is shown and we have to find out the index of refraction of the material x.
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So, the light travels from x to water.
00:22
So, in the material x, the angle of incidence is i, which is equal to 90 degree minus 65 degree, which is 25 degree and in the water, the angle of refraction is 45 degrees.
00:41
So, from snell's law, sin i upon sin r will be equal to refractive index of water upon refractive index of material x.
00:58
Now, we put the values.
01:12
From this, we get the index of refraction of material equal to 2 .23.
01:22
For the second part, we have to find out the angle, which the light makes with the normal in the air when it exits water.
01:33
When the ray of light moves in water, it makes an angle 45 degree with the normal, which means the angle is 45 degree with the vertical...