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This is really just for Paddy as I haven’t seen him on Steam for a while and because he’s our resident Physicist.
I’ve got a question from a paper which i got wrong but I was almost sure was right, so I just wanted to check this with you.
You have two waves of equal amplitude superpositioned on each other (this isn’t how the question is worded, so hopefully you know what I mean), and one is one quarter of a wavelength out of phase. Is the resultant wave bigger, smaller or the same in amplitude?
without wanting to over explain, new max amplitude = (2 x max amplitude) x (cos (.5 angle in radians))
90 degrees is pi/2 radians, 45 degrees is pi/4 radians so if we take max amplitude as 1, then it becomes
2x(cos (pi/4)) = 1.4
if amplitude was 2 then it becomes 2.8 etc.
My original answer of increase by 1/4 was a bit out, it was only when I actually put the numbers in the formula that I realised by how much.
for a visual demonstration go here and scroll down to phase difference applet
Incase you don’t get my steam message, sorry i wasn’t about this evening but I was out for post exam drinks and had to make sure i got fucked. Thanks for the formula, i’ll have a wee play around with that tomorrow to see what I get, but I as my method was a little more simplistic (when drawing the wave) perhaps you could confirm it’s validity. If I draw a line from the x axis to the wave front above the axis (i’m may be making up terms here, hope it makes sense), and draw another to the wave front below the axis, measure both and give the measurement below the axis a minus; is the resultant wave the sum of both at any given point?
Forgive me if that’s double dutch, I’m a little pished.
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