If a source of light is approaching us at 3,000 km/sec, then all its waves are
A) blueshifted by 1%.
B) blueshifted out of the visible spectrum into the ultraviolet.
C) redshifted by 1%.
D) redshifted out of the visible into the infrared.
E) not affected, as c is constant regardless of the direction of motion.

Question

Quizplus · Accepted Answer

The Doppler effect causes the wavelength of light from an approaching source to decrease, which is perceived as a shift towards the blue end of the spectrum. The specific percentage shift depends on the relative speed of the source to the speed of light (300,000 km/s). At 3,000 km/s, this is 1% of the speed of light, leading to a 1% blueshift.

If a Source of Light Is Approaching Us at 3,000