The spectral line of hydrogen producing the quasar absorption lines in most studies has a laboratory wavelengt

Question

The spectral line of hydrogen producing the quasar absorption lines in most studies has a laboratory wavelength of 122 nm. If a hydrogen cloud is at a distance of 1 billion light-years,
a. use Hubble's Law to find the recession velocity of this cloud.
b. What is the redshift of the cloud?
c. At what wavelength will the absorption occur?

Answer 1

Hi. These are three good things to understand but all are dependent on the actual diameter (radius) to the limit of visibility.