Open the simulation "Bending Light" at PhET. Use the address above or use Google. Leave the default for entry material at "Air". Choose "Glass" for the exit material (See pic on right). Record the index of refraction of glass into Table 1
Choose the protractor and set the laser to an angle of incidence, θ1, at 30°. Recall: angles are always measured from the Normal.
Ignore the reflected ray (the ray that remains in air). Using the protractor, measure the angle of refraction, θ2, of the laser and record in Table 1.
Repeat steps 4 and 5 of this lab for 4 more angles of incidence of your own choosing. Record the results in Table 1.
Entry Material Air Trial nglass θ1(degrees) θ2(degrees) Sin θ1 Sin θ2 n2
1 1.52 30 19 .5 .32 1.5
2 1.52 20 13 .342 .224 1.52
3 1.52 40 25 .642 .422 1.52
4 1.52 50 30 .766 .5 1.53
5 1.52 60 35 .866 .573 1.51
Observations and Calculations:
Classify the bending of light as exhibited by the ray diagrams. According to your data, is light refracted away from or toward the normal as it passes at an angle into a medium with a higher index of refraction?
Calculate sin θ1 and sin θ2 for each trial. Record the results in Table 1.
Calculate n2 for each trial. Record the results in Table 1.
Compare the values for index of refraction of glass for each trial (values in last column). Is there good agreement between them? Would you conclude that index of refraction is a constant for a given medium?
Compare your calculated n2 with the given index of refraction, nglass. Do they agree? Explain why it does or doesn’t.
What if you conducted this experiment (Part A) under water? Compare and contrast the results you get in such a situation to the results you have from this lab.