THE DOPPLER EFFECT

1 mark · Easy

What happens to the frequency of light from a galaxy moving away from Earth?

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Correct option: The frequency decreases

Common mistakes: Choosing 'increases' instead of 'decreases'

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Marking points

B1 · 1 mark · Frequency decreases as the galaxy moves away (red-shift).

Worked solution

As a galaxy moves away, the frequency of the light decreases due to the red-shift.