Question

3) A 40,00o kg spacecraft travels to a planet that is 1o light-years away. The one-way trip takes 5 years in the reference system of the spacecraft. The spacecraft uses a radio transmitter with a wavelength of 8.o cm to communicate with earth. What are the wavelength, frequency, and energy of the radio photons as observed back on earth?

Answer 1

Given that mass = 40 00 kg improper length l� = l squareroot 1- beta^2 (beta = v /c) L 10 ly, l� = 5 l y beta squareroot 3/2 doppler shift ohm_obs = ohm_source squareroot 1 - beta/1 + beta = 1 .005 times 10^9 H z Rightarrow lambda_obs = 0.2986 m = 29.86 cm epsilon obs h ohm = 4.146 times 10^- 6 e v