A sound detector is placed on a railway platform. A train, approaching the platform at a speed of 36km/h sounds its whistle. The detector detects 12 kHz as the most dominant frequency in the whistle. If the train stops at the platform and sounds the whistle, what would be the most dominant frequency detected? The speed of sound in air is 340m/s.
The observer (detector) is at rest with respect to the medium (air). Suppose the dominant frequency produced by the train is f0. This will be the ...
From the equation for Doppler effect, we arrive at the final answer step by step.