As you have learnt in the text, the principle of linear superposition of wave displacements is basic to understanding intensity distributions in diffraction and interference patterns. What is the justification of this principle ?

In Young's double slit experiment , the two coherent sources have different intensities . If the ratio of maximum intensity to the minimum intensity in the interference pattern produced is 25 : 1 . What was the ratio of intensities of the two sources ?

The displacement of two sinusoidal waves propagating through a string are given by the following equation y_1 = 4 sin (20 x - 30 t) , y_2 = 4 sin (25 x - 40 t) .where x and y are in centimeter and t in second When these two waves interfere , what are the maximum and minimum values of the intensity ?