Refraction of light (re) Flashcards
What is the normal?
90 degrees to the surface + doesn’t refract
ray of light > water = ?
slows down + refracts
ray of light < water = ?
speeds up + refracts
Which lens focuses light?
convex
Which lens diffracts light into a spectrum of colours?
prism
Which lens lens cause light to diverge?
concave
What type of material cause light to refract?
transparent
Formula for refractive index?
n = c/cs
(c = speed of light)
(cs = velocity of light in material)
What is snell’s law?
When ray of light passes from less dense to more dense, speed change ( slow down) & direction bend toward normal
Equation of snell’s law?
n1c1 = n2c2
or
n1sinθ1 = n2sinθ2
theta obviously correlates to the angles n shit okay???
Why mirror reflect?
Cuz angle of incidence ig?
Light in glass block explanation please?
Material is denser, light slow down and refracts
Light in prism explain damn
Blue light refracts more?
Spectrum made and refracts all colours cuz diff wavelengths
What happens if the angle of incidence is smaller than the critical angle?
- Most light refracted out of block
- Some light reflected (weak ray)
What happens if the angle of incidence is same as critical angle?
- Refracted ray bent through angle of 90° from normal
- Refracted ray weaker than reflected
What happens if the angle of incidence is bigger then critical angle?
- No refraction
- Total internal reflection (boundary surface acts like normal mirror)
4 things of multimode optical fibres?
- Core
- Cladding
- Buffer
- Jacket
What da core?
- glass/plastic with higher index of refraction than cladding
- Carries the signal
What cladding?
- Glass/plastic with lower index of refraction than core
- To allow total internal reflection
What buffer?
- Protects fiber from dmg&moisture
What jacket
- Holds 1/more fibers in a cable
Why multimode fibre more effective short distance than long?
At long, signal get degraded (more spread out) so has to be boosted to prevent output of being discreet
Relationship of time taken to travel thru fibre and the angle to axis of ray?
The steeper the angle to the axis, the longer the light has to travel
Difference between monomode & multimode optical fibres?
Monomode = 1 light mode
Multimode = multiple light modes
so damn obvious shut up
(was last year me this pathetic ,’:)
How can monomode fibres be used at greater distances and still transfer info at greater speed?????????
- 1 single mode
- Reduces data loss cuz overlapping of modes of light
- Light no need reflection so no speed changes ig?