Snell's Law Experiment
Project: Practical Investigation
Aslam Khan, Keenan Wong and Jinhyuk Yeh
2013
Aim: To verify Snell’s Law and find the relationship between angle of incidence and the angle of refraction, for monochromatic light passing from air into Perspex.
Hypothesis: As the angle of incidence increases so will the angle of refraction (directly proportional).
Apparatus:
* Laser (Monochromatic light) * Rectangular Perspex * Ruler * Pencil * Paper * Protractor * Calculator
Method:
1. Place your Perspex in the middle of a piece of paper. 2. Use a sharp pencil to draw its outline. 3. Remove the Perspex from the paper. 4. Use a protractor to draw the line that is normal from the long end of the rectangle. 5. Turn the laser on. Place the laser on the paper so that the laser line is projected onto the normal line and intersects the Perspex outline. 6. Place the Perspex on the rectangle. Ensure that it is straight and lines us with your outline and perpendicular to the normal. 7. The laser light should not be refracted; it should be a straight line (you put the laser perpendicular to the Perspex). 8. Now, choose an angle of incidence, draw the line and put the laser light over it (it must go through the point of intersection between the normal and the Perspex).
9. Now draw a dot where the laser light emerges from the Perspex (as shown in the diagram). 10. Remove the Perspex from the paper. Draw a dotted line connecting the normal and the dot you just made (emerging dot line). Extend the refracted ray. 11. Measure the angles of incidence and the angles of refraction. 12. Use your practical results to verify Snell’s Law.
Results:
*Refractive index for Perspex is 1.5.
Experiment 1 n1 sinθ1 = n2 sinθ2
1 sin30° = n2 sin19.5°
∴n2 =1.497 (Refractive Index)
Experiment 1 check
1.497 sin 19.5 = 1.5 sin19.5°
0.4997 ≈ 0.5
Experiment 2 n1 sinθ1 = n2 sinθ2
1 sin60° = n2 sin35°
Aslam Khan, Keenan Wong and Jinhyuk Yeh
2013
Aim: To verify Snell’s Law and find the relationship between angle of incidence and the angle of refraction, for monochromatic light passing from air into Perspex.
Hypothesis: As the angle of incidence increases so will the angle of refraction (directly proportional).
Apparatus:
* Laser (Monochromatic light) * Rectangular Perspex * Ruler * Pencil * Paper * Protractor * Calculator
Method:
1. Place your Perspex in the middle of a piece of paper. 2. Use a sharp pencil to draw its outline. 3. Remove the Perspex from the paper. 4. Use a protractor to draw the line that is normal from the long end of the rectangle. 5. Turn the laser on. Place the laser on the paper so that the laser line is projected onto the normal line and intersects the Perspex outline. 6. Place the Perspex on the rectangle. Ensure that it is straight and lines us with your outline and perpendicular to the normal. 7. The laser light should not be refracted; it should be a straight line (you put the laser perpendicular to the Perspex). 8. Now, choose an angle of incidence, draw the line and put the laser light over it (it must go through the point of intersection between the normal and the Perspex).
9. Now draw a dot where the laser light emerges from the Perspex (as shown in the diagram). 10. Remove the Perspex from the paper. Draw a dotted line connecting the normal and the dot you just made (emerging dot line). Extend the refracted ray. 11. Measure the angles of incidence and the angles of refraction. 12. Use your practical results to verify Snell’s Law.
Results:
*Refractive index for Perspex is 1.5.
Experiment 1 n1 sinθ1 = n2 sinθ2
1 sin30° = n2 sin19.5°
∴n2 =1.497 (Refractive Index)
Experiment 1 check
1.497 sin 19.5 = 1.5 sin19.5°
0.4997 ≈ 0.5
Experiment 2 n1 sinθ1 = n2 sinθ2
1 sin60° = n2 sin35°