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In the early 1960s the strange optical emission lines from starlike objects that

ID: 1901976 • Letter: I

Question

In the early 1960s the strange optical emission lines from starlike objects that also were producing trementdous radio signals confused scientists. Finally, in 1963 Maarten Schmidt of the Mount Palomar observatory discovered that the optical spectra were just those of hydrogen, but redshifted because of the tremendous velocity of the object with respect to Earth. The object was moving away from Earth at a speed of 50,000 km/s! Compare the wavelengths of the normal and redshifted spectral lines for the K? and K? lines of the hydrogen atom.

K? K?
normal spectral lines ? nm ? nm
redshifted spectral lines ? nm ?nm

Explanation / Answer

normal spectral lines:

K = 122 nm

K = 103 nm


redshifted spectral lines:

o/e = ((1+(v/c))/(1-(v/c))) = ((1+5e7/3e8)/(1-5e7/3e8)) = 1.1832

K' = 1.1832*122 nm = 144.4 nm

K' = 1.1832*103 nm = 121.9 nm