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Index of Refraction

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Investigating the index of refraction of a semicircular acrylic plastic block

| A1 | A2 | A3 | EX | | | | A | | | | EV | | | |
Name: _Felix Koay_ Date: March 5th, 2015 Topic: 4.3 Design In this experiment you will investigate the relationship between the angle of incidence and the angle of refraction of a ray of light when it passes through a semicircular piece of acrylic. An initial hypothesis would suggest that as you increase the angle of incidence, the angle of refraction would also increase, but certainty not proportionally. During the physics lessons you learnt the relationship between the angle of incidence θi and the angle of refraction θr is given by Snell’s law, which states that

Where n1 is the refractive index of the medium from where the ray of light enters a different medium and n2 is the refractive index of that different medium. (Usually called medium 1 and medium 2).

In order to verify this law experimentally, you could design an experiment based on that relationship. Selecting the right variables would allow to plot a graph of sin θr against sinθi and the gradient of the line would allow you to determine the value of the index of refraction of the piece of glass. The next sketch graph justifies this statement.

With the aid of the gradient, you could determine an experimental value of index of refraction of the acrylic block. This result could be compared to the value stated by the manufacturer of the block, or a standard value given in a textbook. This allows to verify experimentally that sin θr is proportional to sinθi and the constant of proportionality should coincide with the ratio of the refractive index of the two media. Selecting and controlling variables Independent variable: Angle of incidence Symbol | Unit of...

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