Final answer:
The question addresses the phase relationship between two coherent radio waves and how they interact to form an interference pattern on a screen. The phase difference (measured in degrees) determines whether the interference is constructive or destructive.
Step-by-step explanation:
The question posed concerns the phase relationship between two coherent radio wave sources and their interference pattern on a screen. Since the sources (S1 and S2) are described as coherent and originating from a single monochromatic source (So), they maintain a constant phase difference and have equal amplitudes. Coherence implies a consistent phase relationship, whereas incoherent sources would have a random phase relationship. The description of the sources' interference pattern on a screen implies that Wave 1 is either ahead of or lagging behind Wave 2 by a certain number of degrees. The phase difference between the waves would dictate the type of interference pattern (constructive or destructive) observed on the screen.
If Wave 1 lags behind Wave 2 by 180° (option a), it means that when Wave 2 reaches its peak, Wave 1 reaches its trough, resulting in destructive interference. If Wave 1 lags behind Wave 2 by 360° (option b), this would mean one full cycle difference, effectively placing them back in phase and resulting in constructive interference. If Wave 1 leads Wave 2 by 180° (option c), Wave 1 is at a trough when Wave 2 is at a peak, again resulting in destructive interference. The same logic applies if Wave 1 leads Wave 2 by 360° (option d), placing them back in phase for constructive interference.
The correct option depends on the specifics of the path difference s1 mentioned in the student's question, which is incomplete in the context provided. Knowing the path difference and the wavelength of the waves would allow us to calculate the phase difference and determine the correct answer.