P3 - Total Internal Reflection Flashcards
Why do optical fibres work?
Total internal reflection.
When can total internal reflection happen?
Only when a wave travels through a dense substance towards a less dense substance.
If the angle of incidence is less than the critical angle..
Most light passes out but a little is internally reflected.
If the angle of incidence is equal to the critical angle..
The ray comes out along the surface. There’s quite a bit of internal reflection.
If the angle of incidence is greater than the critical angle..
No light comes out. It is all internally reflected.
How do you measure the angle of incidence and angle of reflection?
From the normal (the light at a right angle to the surface).
What is the relationship between angle of reflection and angle of incidence?
They’re the same.
How do optical fibres work?
They bounce waves off the sides of a thin inner glass core from one end to the other.
