Optical Fibres and Prisms Use Total Internal Reflection

Question 1

OF - What do optical fibres made of plastic or glass consist of?

Answer 1

A central core surrounded by cladding with a lower refractive index

Question 2

OF - The core of the fibre is so narrow that the light signals passing through it will?

Answer 2

always hit the core-cladding boundary at angles higher than C - so the light is always totally internally reflected

Question 3

OF - When does it only stop working?

Answer 3

If the fibre is bent too sharply

Question 4

P - How does a periscope work?

Answer 4

Total internal reflection allows us to use prism to see objects that aren’t in our direct line of sight

Question 5

P - The ray of light travels into one prism where…

Answer 5

It is totally internally reflected by 90°

Question 6

P - Where does it then travel to?

Answer 6

Another prism lower down and is totally internally reflected by another 90°

Question 7

P - Where is the ray now travelling?

Answer 7

Parallel to its initial path but at a different height