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Question: 

A galaxy is moving away from Earth. The “blue” hydrogen line at 434 nm emitted from the galaxy is measured on Earth to be 455 nm.

  1. How fast is the galaxy moving?
  2. How far is it from Earth based on Hubble’s law?

Source: Giancoli, Douglas C., Physics: Principles with Applications, 7th Edition, 2014.

Quick Answer: 

$0.047c$

Giancoli 7th Edition, Chapter 33, Problem 24

(2:15)

Chapter 33, Problem 24 is solved.

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Comments

There is a part b to this problem. Bye the way, thank you for your videos! They have proven to be very useful in my studies.

Hi matthewgoffena, thanks a lot for noticing that part b) is missing. I've flagged this solution, and will fill in the missing part some other time.

Thanks also the great feedback. I'm really pleased the videos are helping with your course!

All the best,
Mr. Dychko