Answer:
radial velocity = 0.533 × [tex]10^{6}[/tex] m/s
Explanation:
given data
observed wavelength = 394.0 nm
rest wavelength = 393.3 nm
solution
we get here radial velocity  by the Doppler effect of light that is
[tex]\frac{\triangle \lambda }{\lambda} = \frac{v}{c}[/tex] Â Â ......................1
v = [tex]\frac{c \times \triangle \lambda }{\lambda}[/tex] Â Â
put here value
v = \frac{c \times (\lambda ' - \lambda  }{\lambda}
v = \frac{3 \times 10^8 Â \times (394 - 393.3}{393.3}
v = 533943.55
v = 0.533 × [tex]10^{6}[/tex] m/s