Refraction

Snell’s Law

.........but as the angle of incidence increases, eventually:

...you reach the critical angle:

This is the same as saying the angle of refraction is 90°

....but

𝑅𝑒𝑓𝑟𝑎𝑐𝑡𝑖𝑣𝑒 𝐼𝑛𝑑𝑒𝑥 ( 𝐴𝑖𝑟 𝑡𝑜𝐺𝑙𝑎𝑠𝑠 )=𝑣𝑎

𝑣𝑔

Refractive Index is the ratio of wave speeds in two mediums:

𝑅𝑒𝑓𝑟𝑎𝑐𝑡𝑖𝑣𝑒 𝐼𝑛𝑑𝑒𝑥 (𝐺𝑙𝑎𝑠𝑠𝑡𝑜 𝐴𝑖𝑟 )=𝑣𝑔

𝑣𝑎

So: 1

𝑅𝑒𝑓𝑟𝑎𝑐𝑡𝑖𝑣𝑒 𝐼𝑛𝑑𝑒𝑥 (𝐴𝑖𝑟 𝑡𝑜𝐺𝑙𝑎𝑠𝑠)𝑅𝑒𝑓𝑟𝑎𝑐𝑡𝑖𝑣𝑒 𝐼𝑛𝑑𝑒𝑥 (𝐺𝑙𝑎𝑠𝑠𝑡𝑜 𝐴𝑖𝑟 )=¿

From before:

When light hits a surface at an angle of incidence bigger than the critical angle then:

TOTAL INTERNAL REFLECTION

None of the light is transmitted ALL the light is reflected

This is the basis of Optical Fibres

DispersionThis is when signals spread out as they travel along the fibre.

This can cause problems with data

1.

2.