The Doppler formula states that the ratio of the velocity of a source to the speed of light is equal to the ratio of the change in wavelength caused by the Doppler shift to the source wavelength, or
2 = Al. A spacecraft has yellow headlights
which radiate 600-nm photons, and is travelling away from a stationary observer. (a)If the spacecraft is travelling at a velocity of 2% of the speed of light (0. 02c), what will be the wavelength observed (in nanometers)?
(b) What is the energy of the photon received by the observer (in Jauls J?