Superposition, interference and path differenceEdexcel International A Level Physics: Mind map

Exam questions on Superposition, interference and path difference

1. Two small loudspeakers, X and Y, are connected to the same signal generator and emit sound of wavelength 0.40 m in phase. A listener stands at a point P that is 3.00 m from X and 3.60 m from Y.
   Explain, using ideas of path difference and phase, why the sound at P is not loud.2 marks
2. A progressive wave has a wavelength of 0.90 m and a frequency of 120 Hz. Two points A and B lie along the direction of travel of the wave, 0.15 m apart.
   Calculate the minimum separation of two points on the wave that are exactly in antiphase.2 marks
3. Two identical dippers, S₁ and S₂, vibrate in phase at 8.0 Hz in a ripple tank, each producing circular waves of wavelength 2.5 cm. A point Q on the water surface is 20.0 cm from S₁ and 25.0 cm from S₂.
   State what is meant by superposition, and explain why the dippers must be coherent to produce a stable interference pattern.3 marks