Question

One of the strongest emission lines observed from distant galaxies comes from hydrogen and has a wavelength of 122 nm (in the ultraviolet region). (a) How fast must a galaxy be moving away from us in order for that line to be observed in the visible region at 366 nm

Answer 1

`v=2.4*10^8m/s`

Step-by-step explanation:

From the question we are told that

Wavelength of emission
`\lambda=122nm`

Observation distance
`d=366nm`

Generally the s equation is given as

`f'=f\sqrt{((1-(v)/(c) ))/(1+(v)/(c) )`

where

F is inversely proportional to T

`d=\lambda\sqrt{((1-(v)/(c) ))/(1+(v)/(c) )`

`(v)/(c) =((1-(\lambda)/(d)))/((1+(\lambda)/(d))`

`(v)/(c)=(1-((122)/(366) )^2)/(1+((122)/(366))^2)`

`(v)/(c)=(0.8888888889)/(1.11111111)`

`(v)/(c)=0.80`

`v=0.80*3*10^6`

`v=2.4*10^8m/s`