Unit 2 - Refraction of Light Flashcards
What is optical density?
A measure of the way light interacts with the material as it passes through it
What is an indicator of a materials optical density?
Refractive index
What is the equation for the refractive index?
n = sin i / sin r
What calculation is used to calculate change in direction for a ray of light when it enters & leaves a medium?
n 1 X sinx 1 = n 2 X sinx 2
What is dispersion?
When different frequencies of light refract by different amounts and split into various colours
What happens to the refractive index as frequency increases?
It increases
What happens to the frequency of a light source as it goes from one medium to another?
It stays constant
What is the critical angle?
The angle of incidence in the material that causes a ray of light to refract into air at 90 degrees
What happens when the angle of incidence is greater than the critical angle
Reflection without refraction
What is total internal reflection
When all light is internally reflected
What are the two equations to calculate the critical angle?
n1 X sinx1 = n2 X sinx2
sinxC = 1/n
Give a use of total internal reflection
Fibre optics
What happens to a waves velocity when it goes from a less dense to more dense medium?
Decreases
