The Doppler effect describes the change in observed frequency of a wave when there is relative motion between the source of the wave and the observer.
Which of the following scenarios illustrates the Doppler effect for sound?
Show answer & explanation
Correct answer: B
Explanation
Correct Answer:
A stationary observer hears a change in the pitch of a siren as an ambulance passes by.
Explanation:
The Doppler Effect is the phenomenon in which the observed frequency of a wave changes due to the relative motion between the source and the observer. When an ambulance approaches an observer, the siren sounds higher in pitch, and when it moves away, the pitch sounds lower. This is a classic example of the Doppler Effect for sound waves.
Key Points:
• The Doppler Effect involves a change in the observed frequency of waves.
• It occurs due to relative motion between the source and the observer.
• The frequency appears higher when the source moves closer.
• The frequency appears lower when the source moves away.
Additional Facts:
• The Doppler Effect was discovered by Christian Doppler in 1842.
• It has applications in astronomy, medicine, and meteorology.
• Red shift and blue shift are examples of the Doppler Effect for light.
Important Questions:
Q1: Who discovered the Doppler Effect?
Ans: Christian Doppler.
Q2: How does the siren sound when an ambulance approaches an observer?
Ans: It sounds higher in pitch (higher frequency).
Q3: What is an example of the Doppler Effect for light?
Ans: Red shift and blue shift.