Refraction

Question 0

Laws of refraction

Answer 0

The normal , ray of incidence , refracted ray all lie on the same plane

Snells law: the sine of the angle of incidence to the sine of the angle of refraction is a constant

Question 1

Refraction

Answer 1

Bending of light as it passes from one medium to another

Question 2

Refractive index (of a medium)

Answer 2

The sine of the angle of incidence to the sine of the angle of refraction (as light passes from a vacuum to a medium)

Question 3

R.i index from a to b is 3

What is the r.i from b to a

Answer 3

1/3

Question 4

3 ways of finding r.i

Answer 4

C1/c2
Real depth/apparent depth
1/sinc

Question 5

C1/c2

Answer 5

C1= speed of light in air
C2= speed of light in medium

Question 6

Critical angle

Answer 6

This is the angle of incidence with a corresponding angle of refraction of 90* when light passes from a DENSER MEDIUM TO A RARER MEDIUM

Question 7

TIR

Answer 7

Total internal REFLECTION
This is when a light ray travelling from a DENSER MEDIUM TO A RARER MEDUIM
strikes the second medium at an angle GREATER than the CRITICAL ANGLE
And is COMPLETELY REFLECTED

Question 8

1/sinC

Answer 8

C = critical angle

Question 9

Prism

Answer 9

-

Question 10

Snells window

Answer 10

Natural Phenomenon of TIR
Divers looking up are looking from DENSER medium TO RARER medium
They can see through the water UP TO CRITICAL angle
If they look at an angle GREATER than the critical angle they WON’t be able to see through
Effect allows a TRANSPARENT CIRCLE OF WATER (snells window)

Question 11

Tir in real life

Answer 11

Safety reflectors

Question 12

Optical fibre parts

Answer 12

Core
Cladding- LOWER R.I THAN CORE so if light tries to escape it will travel from DENSER TO RARER medium causes it to BEND AWAY from normal and return to core by TIR
Buffer coating- PROTECTS the fibre which transfers very expensive info

Question 13

Optical fibres

Answer 13

Pure long thin strands of glass

Question 14

How optical fibres work

Answer 14

Light enters core at Angle GREATER than critical angle
TIR occurs
Light reflects back and forth as it moves through fibre but ALWAYS stays WITHIN CORE
Continues for many KILOMETRES until it reaches SOURCE
#diagram

Question 15

Ways light can escape from optical fibre

Answer 15

It BENDS TOO MUCH light strikes core at angle LESS than critical angle no TIR occurs leading to loss in valuable information

If two optical fibres’ CORES TOUCH they act as 1 MEDIUM causing loss of info

Question 16

Why optical fibres rather than copper fibre

Answer 16

More flexible 
No electricity needed There is no fire risk 
Cheaper
Can carry more info
Durable