Soundwaves Flashcards
Speed of sound
343 meters per second
What is sound?
Pressure fluctuations in the air.
What is frequency (hz)
Air fluctuations or variations per second.
Also described as the wave length, lambda (λ).
How do you calculate the wavelength? (λ)
λ=C/F
(The wavelength = the speed of sound divided by the frequency)
Eg 20hz would be 343/20=17.15
So the the wavelength is 17.15m
So in turn C =F x λ
Do decibels add together linearly?
No decibel is logarithmic
Sound waves are created when there is a difference change in a medium. What is a medium?
Gas, liquid & solid
How do speaker cones create sound?
They create a pressure difference by disturbing the air particles in front of it.
What is the disturbed air?
Vibrating air molecules that the reflect / absorb until all energy is depleted
What happens when a wave encounters an object.
It will bounce off (reflect) or pass through. Or both.
If the surface is 10x smaller than the wavelength of a particular frequency. What will happen to it?
Pass straight through
If an object is half the size of the wavelength. What happens when they meet?
The object will reflect
What is phase?
The position of a point in time on the cycle of a sound wave.
What will happen when 2 sound waves collide with the same frequency’s depending on their phase?
They will add or subtract
What happens if 2 identical wave forms are 180 degrees out of phase?
will cancel each other out completely when summed due to destructive interference.
This means that the result of the two signals mixed together is silence
How does temperature effect the speed of sound
Heat, like sound, is a form of kinetic energy. Molecules at higher temperatures have more energy and can vibrate faster and allow sound waves to travel more quickly
