Frequence of light of galaxy receding from earth

AI Thread Summary
Most galaxies are receding from Earth, affecting the frequency of light they emit. For a galaxy emitting orange light at 5e14 Hz and receding at 3325 km/s, the frequency observed on Earth can be calculated using the formula f' = f (1 - v/c). The initial calculation resulted in an incorrect frequency due to a possible error in conversion or calculation. It's noted that the speed of 3300 km/s is small relative to the speed of light, indicating the observed frequency will be slightly less than 5e14 Hz. Clarification is needed on the term "fHz," as it appears to be a misunderstanding in the calculations.
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Homework Statement



Most of the galaxies in the universe are observed to be moving away from Earth. Suppose a particular galaxy emits orange light with a frequency of 5e14 Hz.

1) If the galaxy is receding from Earth with a speed of 3325 km/s, what is the frequency of the light when it reaches Earth?

Homework Equations



f ' = f ( 1 - v/c)

The Attempt at a Solution


I did:

f ' = 5e14 (1- 3.325e6/3e8) then converted Hz to fHz and got 4.9e29 but it was wrong.
 
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finger+calculator error

You need to have an estimate of the answer to know if you hit the wrong buttons.
3300km/s is tiny compared to light speed, so 1-v/c is going to be only slightly less than 1, so your answer is going to be slightly less than 5E14.

"then converted Hz to fHz"
what does this mean? whatever it means it was wrong
 


i reworked it and no clue what I am doing wrong. and the answer says it's in fHz
 

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