Use the relativistic Doppler formula for light emitted

[eit32]

6) Using Hubble’s law, estimate the wavelength of the 590 nm sodium line emitted from galaxies (a) 2*10^6 lightyears away from Earth, (b) 2*10^8 lightyears away, and (c) 2*10^9 lightyears away.
** Use the relativistic Doppler formula for light emitted from a receding source)

 

[astrorob]

You should probably post an attempt at solving..

Start by using Hubble's law to find the recession velocity at each distance then use the relativistic doppler formula to find the wavelength shift for each.