In a laboratory, the balmer-beta spectral line of hydrogen has a wavelength of 486.1 nm. if the line appears in a star's spectrum at 486.4 nm, what is the star's radial velocity (in km/s)? (enter the magnitude.) km/s is it approaching or receding? approaching receding is this a blueshift or a redshift? blueshift redshift

185.15 km/s

It is receding, that's a redshift

Explanation:

The radial velocity V of a star can be calculated by the formula:

V = c·Δλ/λ₀

Where c is the speed of light (3*10⁸m/s), Δλ is the wavelength shift (the difference between the wavelengths), and λ₀ is the wavelength that is not shifted (in this problem, 486.1 nm)

If we put the given data in the equation we're left with:

V =

V = 185147.09 m/s

Converting the velocity to km/s:

= 185.15 km/s