Red Shift Problem 2

Question

Given that the light from the Sun peaks at 0.5 microns, where would the light from a Sun-like star peak, if it were receding from Earth with a red-shift of 4?

Answer

The red-shift is defined as

• redshift = ( observed wavelength - true wavelength ) / true wavelength

We can re-arrange this equation as

• observed wavelength = true wavelength (1 + redshift)

Therefore:

• observed wavelength = true wavelength (1 + 4)
  
  
• observed wavelength = 0.5 microns (1 + 4)
  
  
• observed wavelength = 2.5 microns