A transmitter sends out 1.8 x 10 7 waves per minute and generates a standing wave pattern. The radio waves travel at the speed of light to a receiver 20.0 km away. Determine: a) the frequency in hertz. b) the period. c) the wavelength. d) the time for one crest to travel from the transmitter to the receiver. e) the number of nodes between the transmitter and the receiver