3B Scientific SEK Optics - Manual (Page 31)

Exercise
Examine at which angle of incidence light is completely reflected when it passes from glass to air!
What do we need?
1 Optical lamp
with power supply unit
1 Base plate
1 Screen
1 Semicircular glass object
(flat design)
1 Single-slot aperture
1 Mask
Conducting the experiment
1. Attach the mask to the screen!
2. Place the optical lamp on the left side of the base plate, so that the light emerges parallel to the
right!
3. Place the screen in front of the optical lamp!
4. Place the semicircular glass object in the middle as marked on the mask!
5. Insert the single-slot aperture into the aperture holder! Complete the table!
6. Adjust an angle of incidence of α = 35° by changing the position of the optical lamp! Determine the
angle of refraction and enter the value in the table!
7. Repeat the experiment by increasing the angle of incidence in steps of 2.5° until the refracted
beam corresponds to the reflected beam! Record at which angle of incidence this phenomenon oc-
curs!
8. Deviate the critical angle for the total reflection from the law of refraction!
9. Give an example for total reflection!
ELWE Physical experiments for education in natural science and engineering
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1 SEG - OP 3.4 Critical Angle for Total Reflection