1.4 The Endoscope

Question 1

What happens to the reflected Ray in total internal reflection?

Answer 1

The angle of incidence is increased beyond the critical angle so no light is refracted, only reflected. Angle of reflection is equal to the angle of incidence

Question 2

What is the critical angle?

Answer 2

The angle of incidence that causes the angle of refraction to be along the boundary/90*

Question 3

What is the calculation for the critical angle

Answer 3

N = 1/sinC

Where n is the refractive index
And c is the critical angle

Question 4

What is a partially reflected Ray?

Answer 4

A light Ray that has been reflected as well as refracted so it is only partially reflected. This is due to the angle of incidence being smaller than the critical angle

Question 5

What is an endoscope?

Answer 5

A device used to look inside a patients body without cutting it open or using keyhole surgery

Question 6

How does an endoscope work?

Answer 6

It contains bundles of optical fibres where visible light waves can be sent down using total internal reflection

Question 7

Name a use of total internal reflection

Answer 7

Fibre optic cables: reflects the light rays totally so none is wasted

Question 8

What are optical fibres?

Answer 8

Very thin glass fibres that are designed to transmit light or infrared radiation. The light rays can’t escape from the fibres. Each fibre reflects the light rays, even if it bends