The relativistic Doppler effect describes how the observed frequency of a relatively moving source changes with respect to the proper frame of the source. In Fig. (1) a satellite is shown to be moving parallel with the ground at a height h with a velocity v toward an observer at O. X, X 4 X 0 Ground 0 h V Figure 1: An approaching satellite moving parallel to the ground is emitting light toward a ground observer. For the approaching satellite, determine the angle for which no Doppler effect is measured. For what speed of particle will this point coincide with the observer ground position (i.e. x = 0)? [3,2 marks] If the satellite emission frequency is 1 Hz and 8 = 1/2, plot a graph of effective frequency against cos for the approaching satellite up to when it is overhead for the observer. [4 marks] The satellite changes its emitter to produce visible light at 500 nm wavelength. Determine the effective frequency for both the approach- ing and receding parts of the trip when the satellite is 100 m away from the observer in ground coordinates. Take the satellite height to be 50 m.