Spectral line

[azatkgz]

1. The problem statement, all variables and given/known data
One of the most prominent spectral lines of hydrogen is H_\alpha line.A bright red light with wavelength of 656.1\times 10^{-9}m.What's the expected wavelength of the H_\alpha line from a star receding with a speed of 3000 km/s?






3. The attempt at a solution

Is it just \lambda=\lambda_o-\frac{\lambda_ov}{c}

[BerryBoy]

1. The problem statement, all variables and given/known data
One of the most prominent spectral lines of hydrogen is H_\alpha line.A bright red light with wavelength of 656.1\times 10^{-9}m.What's the expected wavelength of the H_\alpha line from a star receding with a speed of 3000 km/s?






3. The attempt at a solution

Is it just \lambda=\lambda_o-\frac{\lambda_ov}{c}

I believe that should be: \lambda=\lambda_o+\frac{\lambda_ov}{c}

When objects move away from the observer, the doppler shift, increases the wavelength (red-shifts it).

Sam