4.4 Wave properties 2 Flashcards
What is superposition?
» Where waves meet and they combine for an instant
What is the principle of superposition?
» When 2 waves meet, the total displacement at a point is equal to the sum of the individual displacements at that point
What is a supercrest?
» When a crest meets a crest - a supercrest is created
What is a supertrough?
» When a trough meets a trough, a supertrough is created
What happens when a trough meets a crest of the same amplitude?
» Total displacement is 0, as the 2 waves cancel each other out
» If they are not the same amplitude it is called a minimum
What is a stationary wave?
» A results of the superposition of 2 waves with the same amplitude and frequency, travelling at the same speed but in the opposite directions
What is a progressive wave?
» A wave which oscillates the particles of the medium that is travelling through
What is a node?
» Points where the displacement is 0
At each node what is the phase difference between the 2 sets of waves?
» 180 degrees so they cancel each other out
What is a minimum?
» When 2 troughs meet at the same point, they superose to produce maximum negative displacement
Why are there gaps in the wavefronts when circular waves superpose?
» Points of cancellation between the trough and the crest
What is interference?
» When waves are continously passing through each other with constant frequency and at a constant phase difference, cancellation and reinforcement occurs at fixed positions
Why do coherent sources of waves produce an interference pattern?
» Because they vibrate at the same frequency, and constant phase dfferences
What is mean by the frequency of a wave?
» Number of oscillations per second through a fixed point
What is one key fact to remember when waves refract/ cross a boundary?
» Frequency remains the same
