Waves Flashcards
What is needed for a standing wave to form?
A standing wave requires to waves travelling in opposite directions with the same wavelength to collide and interfere with each other causing nodes and anitnodes, this is the principle of superposition
How would you find the phase difference on a standing wave?
The phase difference on a standing wave is always either π/2 or π rads out of phase just with differing amplitudes
What happens as a light ray enters a medium with a higher refractive index?
If a light ray goes from low to high in terms of refractive index, it will slow down and consequently, the wavelength will also decrease by v = fλ, the ray with then bend towards the normal if it is coming in at an angle relative to that normal due to the wave front closest to the normal hitting it and slowing down first as it enters the new medium while the part of the front furthest from the normal still travels at it’s old speed for the longest time
How does a fibre optic cable work?
Fibre optics work by abusing total internal reflection as we have a small glass core surrounded by a cladding which is glass but it has a slightly lower refractive index than the core, this is to make the critical angle higher such that more light rays can escape from the core, this is to avoid multipath dispersion
What is multipath dispersion?
Multipath dispersion is where many light rays take different paths through a fibre optic and so take different times to get through the fibre, causing the duration of the signal to increase and so makes the signal overall less clear
What is needed for polarization to occur?
A transverse wave, ie a light wave, and a polarizing filter to polarize the incoming light rays in one plane
