Waves Flashcards
What does the angle of incidence equal if it reflects of the boundary and remains in the same medium
Angle of refraction
Conditions of superposition
Same wave type
Constant phase difference
Opposite direction
Same frequency / speed
Same amplitude
Width of central Maxima compared to subsequent maxima
Double
Single slit diffraction pattern
Larger central Maxima, intensity decreases rapidly either side
Is red or blue light more likely to experience TIR and why?
Blue light, as it has a larger refractive index and therefore lower critical angle.
How to find the wavelength of a longitudinal wave?
The distance between the centre of 2 corresponding compressions
Impact of increased wavelength on central maxima
Wider, but less intense
Coherent sources: 2 conditions
Same frequency/wavelength
Fixed phase difference
Difference between microwaves and soundwaves
Longitudinal and transverse
Microwaves can travel through a vacuum (sound needs matter)
Microwaves can be polarised
What’s the fundamental frequency
The 1st harmonic / the lowest frequency of a periodic waveform
When ∅i = ∅r
Reflection
Diffraction def
The spreading of waves when they pass through a gap
Antinode def
A position of maximum displacement in a stationary wave
Optical fibre def
A thin glass fibre through which signals are passed through and usually have a cladding surrounding them
Phase difference def
The difference in phase between two points on a wave.
Polarisation def
The restriction of a wave so that it can only oscillate in a single plane.
Longitudinal wave def
A wave with oscillations that are parallel to the direction of energy propagation.
Transverse wave (secondary wave)
Longitudinal (primary wave)
Why use light rather than electrons in an optical fibre?
Less energy lost that would be caused due to heating from the resistance of the wire it would travel through compared to signal degradation.
Also slower (slightly)
Why is infrared used for optical fibres more often than light?
Easier to restrict than monochromatic light therefore easier to stop material dispersion.
Functions of core and cladding in optical fibre
Core: where EM waves travel (transmission medium)
Cladding: provides lower refractive index at the cores boundary to cause TIR and offers protection from scratching which could lead to light leaving the core.
Sound waves can perform TIR and they would travel in a low medium and have a high refractive index medium as there cladding (opposite to transverse waves, since sound waves travel faster through a medium)
Fringe spacing def
The distance between two adjacent bright/dark fringes
