K.C.S.E Physics Q & A - MODEL 2012PP2QN014

K.C.S.E Physics Q & A - MODEL 2012PP2QN014

​(a) Figure 12, shows a displacement - time graph for a progressive wave.

​(i) state the amplitude of the wave. 
(ii) determine the frequency of the wave. 
(iii) given that the velocity of the wave is 20m/s,determine its wavelength.
(b) Figure 13 shows two identical dippers A and B vibrating in water in phase with each other. The dippers have the same constant frequency and amplitude, The wavesproduced are observed along line MN:

​It is observed that the amplitudes are maximum at points Q and S, and minimum at points P and R. 
(i) explain why the amplitude is maximum at Q. 
(ii) state why the amplitude is minimum at R. 
(iii) State what would happen if the two dippers had different frequencies. 

answer

​(b) (i) Waves at Q are in phase q so there is constructive interference, 
(ii) Waves are out of phase hence destructive interference, 
(iii) Interference pattern would disappear.