Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
The observed frequency refers to the frequency at which an observer perceives a sound wave or light wave due to relative motion between the source and observer.
The Doppler effect describes how the perceived frequency of waves changes when there is relative motion between the source of waves and an observer.
Redshift/Blueshift: Redshift refers to an increase in wavelength (and decrease in observed frequency) of light waves due to objects moving away from us. Blueshift refers to a decrease in wavelength (and increase in observed frequency) of light waves due to objects moving towards us.
Sonic Boom: A sonic boom occurs when an object moves faster than the speed of sound, creating shockwaves that produce a loud noise.