Question

If you start with two sinusoidal waves of the same amplitude traveling in phase on a string and then somehow phase-shift one of them by 5.4 wavelengths, what type of interference will occur on the string?

Answer 1

Explanation:

Two waves with the same wavelength are in phase if there phase difference is zero or an integral multiple of wavelength. Thus the integer part of any difference expressed in wavelength can be discarded.

The phase difference of 5.4 wavelength is equivalent to is one of 0.4 wavelength thus the interference is an intermediate interference close to fully destructive.