4.3 Absorption and Trasmission 5/9 Flashcards
(14 cards)
What is absorption?
When a wave is converted to another form of energy as it passes through a medium
What appears to happens to a wave during absorption?
The wave seems to “disappear” as it enters another medium
But it actually changes into a different form of energy
Provide an example of absorption.
Light energy hitting a black car, where it is converted into heat energy
Can all waves be absorbed?
Yes, all waves can be absorbed
What happens to the volume of sound waves as you move further from the source? Why?
They get quieter due to absorption
What is transmission?
When a wave passes from one medium to another
What is interference?
Interference is when two or more waves hit each other and interact
What are the two types of interference?
Constructive and destructive
How do noise cancelling headphones utilize interference?
They produce a signal that is “out of phase” with background noise to cancel it out.
This is destructive interference
What is the principle of superposition?
When two waves meet, you add their amplitudes
positive + positive = increased amplitude, whereas a positive + negative = decreased amplitude (cancel each other out)
What is “negative” amplitude
The part of the wave below the equilibrium line
When two wave pulses cross each other in places where a wave crest and a wave trough meet, what happens?
Destructive interference
The crest and trough CANCEL each other
What is constructive interference?
When two waves meet and their crests are in phase, causing their amplitude to increase
If two waves interact (each with amplitudes of 4 cm ) interact and create constructive interference, what will the amplitude of the combined wave be?
4cm + 4cm = 8 cm
