Question

You record the spectrum of a star and find that a calcium absorption line has an observed wavelength of 394.0 nm. This calcium absorption line has a rest wavelength of 393.3 nm. What is the approximate radial velocity of this star?

Answer 1

radial velocity = 0.533 ×
`10^(6)` m/s

Step-by-step 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

`(\triangle \lambda )/(\lambda) = (v)/(c)` ......................1

v =
`(c * \triangle \lambda )/(\lambda)`

put here value

v = \frac{c \times (\lambda ' - \lambda }{\lambda}

v = \frac{3 \times 10^8 \times (394 - 393.3}{393.3}

v = 533943.55

v = 0.533 ×
`10^(6)` m/s