Determine the effect of nuclear mass on the first line of the Balmer series of h

Question

Determine the effect of nuclear mass on the first line of the Balmer series of hydrogen by CALCULATING ITS WAVELENGTH SHIFT for deuterium and tritium. Note: There are two answers to this problem and they are in angstroms if that helps. I need to know how to calculate the wavelength shifts. Thanks 8)

Explanation / Answer

Standard Doppler effect equation The standard equation for the observed frequency of a waveform for a moving source is: fo = fv/(v ± vs) where fo is the observed frequency v is the velocity of the waveform vs is the velocity of the source f is the emitted frequency ± is plus or minus; plus (+) is used when motion is away from you and minus (-) is used when motion is toward you (See Doppler Effect Equations for Sound for more information on that application.) Blue-shift equation The equation for the observed frequency of a light wave when the source is traveling toward you (blue-shift) is: fb = f(1 + vb/c) where fb is the observed blue-shift frequency vb is the velocity toward you c is the speed of light c >> vb (c is much greater than vs) Red-shift equation The equation for the observed frequency of a light wave when the source is traveling away from you (red-shift) is: fr = f(1 - vr/c) where fr is the observed red-shift frequency vr is the velocity away from you Note that "-" and "+" are reversed as compared to the standard Doppler effect equations. This is a result of the approximation Example When heated, the various chemical elements give off light in a specific series of wavelengths or spectral lines. Astronomers study a number of spectral lines, but for our purposes, we will use the Hydrogen spectral line of ? = 434 nm, which is in the violet region of the visible spectrum. If a distant galaxy is moving away from us at approximately 50,000 km/s and we approximate the speed of light as c = 300,000 km/s, then the resulting wavelength will be: ?r = ?c/(c - vr) Substitute values into equation. ?r = 434*300000/(300000 - 50000) ?r = 520.8 nm The line has shifted from violet to green. Other spectral lines would also have shifted toward the red end of the spectrum.

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