Question

A car makes sound as it moves toward a stationary observer. What best describes the sound wave heard by the observer compared with the sound heard by the car’s driver?

higher frequency; shorter wavelength
higher frequency; longer wavelength
lower frequency; shorter wavelength
lower frequency; longer wavelength

Answer 1

When a car is moving toward a stationary observer, the sound wave compresses as it approaches, resulting in a phenomenon known as the Doppler effect. The observer hears a sound with a higher frequency than what the driver hears inside the car because the sound waves are being compressed.

Therefore, the best description of the sound wave heard by the observer compared to the sound heard by the car’s driver is:

**higher frequency; shorter wavelength.**

This is because a higher frequency corresponds to a shorter wavelength in sound waves.