Lesson: The Doppler Effect
In this lesson, we will learn how to calculate the change in the frequency of waves that are emitted by a source that is moving relative to the observer.
Sample Question Videos
Worksheet: 17 Questions • 6 Videos
A hawk swoops down to catch a mouse, screeching as it does so. The hawk approaches the mouse at a speed of 25.0 m/s, and the frequency of the screech is 3,500 Hz. What is the frequency of the screech as heard by the mouse? Use a value of 331 m/s for the speed of sound in air.
What is the speed of the train?
If the train’s speed remains constant, what frequency does the observer measure as the train recedes from them?
An ambulance’s siren has a frequency of 1.00 kHz. The ambulance is approaching the scene of an accident at a speed of 70.00 mph. A nurse is approaching the scene from the opposite direction to the ambulance at a speed of 7.00 m/s. Determine the frequency of the siren as measured by the nurse. Use a value of 343.00 m/s for the speed of sound in the region around the accident scene.