(a) State the principle of superposition of waves.
(b) Two sinusoidal waves of the same frequency and equal amplitude A travel simultaneously through the same medium. Using a symbolic expression for the two displacements, explain how the phase difference θ between the waves decides the value of the resultant amplitude at a point.
(c) For which values of θ will the resultant amplitude become (i) maximum, (ii) minimum? Give the corresponding physical interpretation of these two special cases.