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# Phase difference question! watch

1. I don't understand that why the answer is C, and why am I getting n as 1.

And taking to be equal to 1, should be 0.5, and n is coming as 1.

2. Using your formula, x, the distance between X and Y is 1.5 wavelengths, so put x = (3/2) lambda in it and you get phi = 3 pi
3. (Original post by Stonebridge)

Using your formula, x, the distance between X and Y is 1.5 wavelengths, so put x = (3/2) lambda in it and you get phi = 3 pi
But what I read was that x IS always less than wavelength, and when any number of wavelengths come into the value of x we eliminate that number of wavelengths. Like for example let us take wavelength as 1, then distance between X and Y is 1.5, so eliminating one gives us 0.5 to be used as x? OR is my concept wrong? :s
4. Two points on a wave can be any number of wavelengths apart, and phi can be any value.
I think what you are thinking of is the fact that, as the cycle just repeats itself, a phase difference of 1.5 wavelengths amounts to the same displacement as a difference of 0.5
But a point at a phase difference of just pi would not be at the same place on the graph/wave as Y, though it is at the same distance below the axis, as will be the points at 2.5, 3.5 4.5 etc.
5. (Original post by Stonebridge)
Two points on a wave can be any number of wavelengths apart, and phi can be any value.
I think what you are thinking of is the fact that, as the cycle just repeats itself, a phase difference of 1.5 wavelengths amounts to the same displacement as a difference of 0.5
But a point at a phase difference of just pi would not be at the same place on the graph/wave as Y, though it is at the same distance below the axis, as will be the points at 2.5, 3.5 4.5 etc.
Hmm, though it's a bit difficult to understand but I'll try to remember it. Thanks.

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