The Refractive Index

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  • Topic: Refraction, Snell's law, Total internal reflection
  • Pages : 4 (981 words )
  • Download(s) : 291
  • Published : April 16, 2013
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The refractive index
The aim of this experiment is to find the refractive index of a glass prism. In this experiment, the independent variable is the angle of incidence, and the dependent variable is the angle of refraction. Theory:

Snell’s law relates the angle of incidence and refraction to the ratio of the velocity of the wave in the different media. The formula for Snell’s law is the following: Sin isinr = v1v2 = n Where i is the angle of incidence, r is the angle of refraction and v1 and v2 are the velocities of the wave in different media and n is the refractive index. Light refracts when it passes from one medium to another. The ratio of the velocity of light in the two media is called the refractive index. Materials and method:

For this experiment we used a half glass circle attached on the center of a laminated paper with a drawn circle around it, a blue/violet laser with a wavelength 447nm and a wood block. First we started by placing the flat side of the half glass circle attached to the paper in front of the laser. Depending on the angle we wanted to find, we used the drawn circle on the paper to decide where to put the laser on the half side of the drawn circle. The angles of incidence we used were 10°, 20°, 30°, 40°, 50° and 60°. First we measured the angle of incidence, where we placed the wood block perpendicular to the ray. To control the variables, the laser should have the same wavelength for all the angles to get the same refractive index and the ray should hit the center of the glass circle, so to check that the ray hits the center of the glass circle, we placed a wood block at the angle of reflection to see if the angle of reflection is the same as the angle of incidence, because we know that the angle of incidence is equal to the angle of reflection. Another thing which makes it easier to hit the center of the glass circle is by placing a paper on the flat side of the circle and see if the ray hits the center of the circle and...
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