Total internal reflection allows signals to travel through optical fibers by causing light that hits the boundary between the fiber's core and cladding at an angle greater than the critical angle to be fully reflected back into the core rather than passing into the cladding. This allows the light to travel down the core and be transmitted without significant loss of signal. Optical fibers have advantages over copper cables for communication lines due to lower attenuation or signal loss over long distances.

1. Total Internal Reflection Explain how total internal reflection allows signals to travel through optical fibres.

2. The arrow behind the beaker The bending pencil The disappearing coin Bending light as an optical illusion These are examples of refraction

3. How does light travel? How do we get around corners?

4. Draw light going from a luminous source to your eye Draw light going from a luminous source onto an opaque object and reflecting into your eye Draw light going from a luminous source through a transparent object into your eye Draw light going from a luminous source ....... Of you looking in the mirror ... Into your eye

5. Mirrors Incident angle  i Reflected angle  r Reflected ray Incident ray If you were looking in a normal bathroom mirror and you could just see your head in the reflection if you stand back will you see more of your body? For you to try at home

6. Total internal reflection Set up the light boxes , use the single slit to create a single beam Use the template to measure the angle of reflection for an angle of incidence of Try and find the critical angle (where the light come back in the same direction) Normal line

7. Fibre optics Reflected rays, not refracted

8. What are the uses of optical fibres? Endoscopes What are the advantages of using optical fibres over copper cable? Communication lines What does attenuation mean and how would this affect optical fibres.