# AS Physics Optics

Define Law of Reflection
Angle of Incidence = Angle of Reflection
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Where are the Angles of Incidence and Reflection measured from?
The ray and the normal
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Define Refraction
The bending of waves due to a change in speed
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What is the Refractive Index of a Substance equation?
N = speed of light in a vacuum/speed of light in a substance ( N = C/Cs)
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What is Snells' Law of Refraction eqaution?
n1sin(angle)1 = n2sin(angle)2
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What is the Refractive Index of Air?
1.000
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Define Critical Angle
Equal to the incident angle within a substance which results in a refracted ray having an angle of refraction of 90 degrees
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When does Total Internal Reflection occur?
When the substance containing the incident angle has the larger refractive index, and the incident angle is greater than the critical angle for the interface
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What is the Critical Angle equation?
Sin(angle)c = n2/n1
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What does a Optical Fibre consist of?
A core of glass surrounded by cladding made of glass of a different refractive index. Light from a laser travels along the optical fibre
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What is the purpose of the Core?
Light travels along the core undergoing TIR at the boundary between the core and the cladding
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What is the purpose of the Cladding?
Prevents light escaping from the optical fibre. Ensures the light can travel significant distnaces
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How can Multiple Path Dispersion be reduced?
By making core of optical fibres very thin- shortens journey of light pulses
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What is the uses of Optical Fibres in Communications?
Information can be transmitted at high speed
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What is the uses of Optical Fibres in Medicine?
Endoscopes - produces more accurate medical diagnoses; produces images of the inside of the body
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## Other cards in this set

### Card 2

#### Front

Where are the Angles of Incidence and Reflection measured from?

#### Back

The ray and the normal

### Card 3

#### Front

Define Refraction

### Card 4

#### Front

What is the Refractive Index of a Substance equation?

### Card 5

#### Front

What is Snells' Law of Refraction eqaution?