← Back to Training
MCQIntermediateLight, Radiation & Spectroscopy
USAAAO — 2016 First Round
Question 17
An active galactic nucleus is observed to produce a hydrogen emission line at 687.2 nm. The rest wavelength of this hydrogen emission line is 121.6 nm. What is its recessional velocity relative to us, in km/s?
Sign in to save your progress.