How fast must you be traveling relative to a source of blue light (480 nm)for the light to appear shifted towards the red by 10 nm?
A)0.02 c
B)0.10 c
C)0.12 c
D)0.96 c
E)0.98 c

Question

Quizplus · Accepted Answer

The shift towards red indicates a redshift, which means the observed wavelength is longer than the emitted wavelength. The change in wavelength (Δλ) is 10 nm, from 480 nm (blue light) to 490 nm (shifted light). The formula for relativistic Doppler shift in the context of light is $\Delta \lambda / \lambda = v/c$, where $\Delta \lambda$ is the change in wavelength, $\lambda$ is the original wavelength, $v$ is the velocity of the observer relative to the source, and $c$ is the speed of light. Plugging in the values, $10 / 480 = v / c$, solving for $v$, we get $v = 0.02c$.

How Fast Must You Be Traveling Relative to a Source