The phase difference between two points on a wave, x1,and x2, is the angle ?0 such that if you shift thephase of one wave by ?0 (in the wave equation) towardsthe other, the two points will line up.

For example, if x2 is to the right of x1 thenthe phase difference between them, ?0, satisfies:

Acos(kx2??0)=Acos(kx1)

Consider a wave on a long wire with a wavelength of 10.0 metres.What is the phase difference between two points that are 5.0 metresapart?

A. ?/4 radians.
B. ?/2 radians.
C. ? radians.
D. 2? radians.
E. None of the above.