VCE Physics critical angle tir, emr, colour addition

1. 6 Critical Angle TIR, EMR
8.3 Critical Angle TIR, EMR, Colour addition

2. TIR
Since the transmitted light enters a less optically dense medium it travels faster and
is refracted away from the normal.
As the angle of incidence is increased, the angle of refraction also increases. This
continues until, at a certain angle of incidence called the critical angle, 𝑖 𝑐 , the
angle of refraction will be almost 90° and the transmitted ray travels just along the
surface of the water.
When a light ray exceeds the critical angle it undergoes total internal reflection
(TIR).

3. Optical fibers are widely used in fiber-optic
communications, where they permit transmission over
longer distances and at higher bandwidths (data rates) than
wire cables. Fibers are used instead of metal wires because
signals travel along them with less loss and are also
immune to electromagnetic interference.

4. How to calculate 𝑖 𝑐
Note: It only exists when you have the light going from a medium with a higher
refractive into a medium with a lower refractive index.

7. electromagnetic radiation (EMR)
Read page 274 of your text book for a description of Electromagnetic
Radiation.

8. EMR Categories

9. Coloured light, different wavelengths

10. Why is the car green?
• A green object is using the light from the sun to show it’s colour. The
suns light is white, so made up of all colours of light.
• A green car absorbs all colours of light other than green. The green is
reflected and is taken in by our eyes.

11. The green car

12. Coloured filters
• Coloured filters have the same effect as coloured objects. The
difference is, rather than reflected the extra light, they let it pass
through.
• They absorb all colours of light except theirs.
• Eg: A red filter absorbs all colours except red and only allows red to be transmitted.

13. Colour addition or mixing light sources

14. Summary