Experiment 7: Introduction to Reflection and Refraction

The purpose of this lab was to study the properties of reflection and refraction using semicircular prism and a source of light.

In this experiment we used:

- Light box

- Semicircular prism

- Protractor

PART ONE:
First we adjusted the light box so that the light waves entered the flat part of the semicircular and exited the curved part. We taped a paper protractor under it so that the center of the flat side was on top of the protractor and on the 0 and 180 degree line. We then turned on the light box and recorded the angle of incidence θ1 and the angle of refraction θ2. We then rotated the prism  and protractor (together) by 4-8 degrees and measured the angles. We did this for a total of ten trials until we reached 80 degrees.  

 

Below is the data collected:

We recorded the values for theta1 and theta2 and found the sin(theta1) and sin(theta2). We then plotted the sin(theta1) vs sin(theta2). 

 The slope of this graph was 1.9944. This slope is the index of refraction of the material that we used. 

PART TWO:

In this part of the experiment we did the same as above except that the light box ray entered the curve part of the semicircular prism and exited the plat side. We recorded the theta1 and theta2 when it was at 0 degrees and then rotated the prism every 4-8 degrees.

We recorded the values for theta1 and theta2 and found the sin(theta1) and sin(theta2). We then plotted the sin(theta1) vs sin(theta2). 

 The slope of the plot is 1.3346 is the index of refraction of the semicircular prism. We were not able to complete all of the trials because at 45 degrees, there was the critical angle where there was no refracted ray.

Conclusion:

The theoretical value for the the index of refraction of the semicircular prism is 1.49.