Two photons of same frequencies moving in same medium have

The two waves of same frequency moving in the same direction give rise to

The two waves of same frequency moving in the same direction give rise to

The two waves of the same frequency moving in opposite direction give rise to

Two harmonic waves travelling in the same medium have frequency in the ratio 1:2 and intensity in the ratio 1:36. Their amplitude ratio is:

Two waves of same frequency and same amplitude reach a common point of the medium simultaneously. If the amplitude of resultant wave is zero then the path difference between the waves will be –

Two sinusoidal waves have the same angular frequeny the same amplitude y_m , and travel in the same direction in the same medium. If they differ in phase by 50^@ the amplitude the resultant wave is given by