A train sounding its horn is moving toward an observer. The pitch of the horn's sound relative to its normal pitch is
A) lower.
B) sometimes higher and sometimes lower.
C) higher.
D) the same.

Question

Quizplus · Accepted Answer

The pitch of the horn's sound is higher due to the Doppler effect, which occurs when a sound source moves towards an observer, causing the sound waves to compress and the frequency to increase.

A Train Sounding Its Horn Is Moving Toward an Observer