Question

When do waves have constructive interference?

Answer 1

lots of videos on youtube - just search for constructive interference

Answer 2

It's not affected by frequency/period, right? What factors cause it to have constructive interference? (can't watch youtube videos, don't have a headphone with me)

Answer 3

Two waves have constructive interference when the phase of one wave is the same as the phase of another wave at the particular point in space that you are considering.

Answer 4

If the two waves have exactly the same frequency then they will always stay in phase. If they have slightly different frequencies they will oscillate between constructive and destructive interference at the measurement point so that the measured intensity at that point varies with time at the "beat frequency".

Answer 5

when waves interact (occupy the same space at the same time) their displacements from equilibrium add like vectors. If they add to make an amplitude greater than the original amplitude, it's called constructive interference; if they add to make a smaller amplitude, it's called destructive interference. If they are the same amplitude and wavelength, and are exactly 180 out of phase, they interfere and result on an amplitude of 0; if they are in phase, the result will be an amplitude of 2x the normal one

Answer 6

A two-dimensional vector notation is used to represent the phase of the wave: The phase angle and amplitude of the first wave at the measurement point gives the angle and amplitude of a two-dimensional vector called a "phasor". The phase angle and amplitude of any further wave that is incident on the same measurement point is represented by a second two-dimensional phasor vector with the same angle as the phase angle of the second wave at that point and the same amplitude as the second wave for that point. Then, as 'Superstar' said, these two vectors can be added vectorially to create a new resultant vector which represents the resulting phase and amplitude of the new wave that is generated at that measurement point as the two waves interfere. It's mathematically useful but it doesn't help you to understand the physics involved because it's just a process that gives an equivalent mathematical result without modelling any physics concept (just to be clear).

Answer 7

Oops, sorry I meant just as 'stan' said. I read 'Superstar' as a name lol