You shine a beam of monochromatic light from Earth to an astronaut friend in orbit. The light your friend receives, relative to light from an equivalent source on the spaceship, is slightly
A)lower in frequency.
B)higher in frequency.
C)weaker but no different in frequency.

Question

Quizplus · Accepted Answer

According to the Doppler Effect, when an observer is moving towards a source of waves (in this case, light), the frequency of the waves increases, and when the observer moves away, the frequency decreases. As the astronaut is in orbit around the Earth, they are moving away from the Earth at a relatively constant speed. Therefore, the frequency of the light received by the astronaut will be lower than what it would be if the astronaut was stationary with respect to the Earth. Thus, choice A is the correct answer.

You Shine a Beam of Monochromatic Light from Earth to an Astronaut