17. 18. 19. A new radio station wishes to place two transmission towers near each other in a central location between several urban areas. These two towers will act as a two-point source. If the majority of the population lies on an axis running eastwest, what orientation should the two towers have in order to maximize the signal reaching the majority of the population? The index of refraction of turpentine relative to air for red light is 1.47. A ray of red light (7L = 6.5 x 107 m) strikes an air-turpentine boundary with an angle of incidence of 40. (a) What is the wavelength of red light in turpentine? (b) What is the angle of refraction in turpentine? The wavelengths of the visible spectrum range from 400 nm to 750 nm. What is the range of the frequencies of visible light