Progressive wavesAQA A-Level Physics: Mind map

Exam questions on Progressive waves

1. A student uses a vibrating dipper to generate straight water waves in a ripple tank. The dipper vibrates at 12 Hz and the student measures the distance between adjacent wave crests on the water surface as 2.5 cm.
   The student doubles the frequency of the dipper. The speed of the waves is unchanged because the depth of water is unchanged. Calculate the new wavelength.2 marks
2. Two buoys, A and B, float on a lake in line with the direction in which a sinusoidal water wave is travelling. The wave has frequency 0.50 Hz and wavelength 8.0 m. Buoy B is 3.0 m further along the direction of travel than buoy A.
   Calculate the time by which the motion of buoy B lags behind that of buoy A.2 marks
3. A loudspeaker produces a continuous pure note of frequency 850 Hz in air, where the speed of sound is 340 m s⁻¹. Two small microphones are placed in a straight line with the loudspeaker, at distances of 1.20 m and 1.50 m from it.
   Calculate the wavelength of the sound and the phase difference, in radians, between the signals at the two microphones.3 marks