ll'l'n7.25. (a) How fast must you be approaching a red trafc light (A = 675 nm) for it to appear yellow (A = 575 nm)? Express your answer in terms of the speed of light. (b) If you used this as a reason not to get a ticket for running a red light, how much of a ne would you get for speeding? Assume that the ne is $1.00 for each kilometre per hour that your speed exceeds the posted limit of 90 km/h. ll\"37.26. Show that when the source of electromagnetic waves moves away from us at 0.600c, the frequency we measure is half the value measured in the rest frame of the source