C.5 Doppler effect

Objective notes

5 learning objectives

—C.5.1—Doppler effect

• Nature of the Doppler effect for sound waves and electromagnetic waves.

—C.5.2—Doppler wavefront diagrams

• Represent Doppler effect with wavefront diagrams for moving source or observer.

—C.5.3—Light Doppler approximation

• For light at low relative speed: Δf/f = Δλ/λ ≈ v/c.

—C.5.4—Spectral line shifts

• Spectral line shifts reveal motion of stars and galaxies.

—C.5.5 (HL)—Mechanical-wave Doppler formulas

• HL: Doppler formulas for sound/mechanical waves.

• Distinguish moving-source and moving-observer cases.