Two coherent sinusoidal waves of equal amplitude 5mm superpose at a point in a medium. The resultant amplitude at the point is observed to be 8mm.
(i) Calculate the phase difference between the two waves.
(ii) Determine the ratio of the intensity at this point to the intensity of a single wave.
(iii) If these two waves were parts of a stationary (standing) wave on a stretched string, would the point under consideration correspond to a node, an antinode, or neither? Justify your answer quantitatively.