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Question
A source of sound moves towards an observer.
Options
The frequency of the source is increased.
The velocity of sound in the medium is increased.
The wavelength of sound in the medium towards the observer is decreased.
The amplitude of vibration of the particles is increased.
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Solution
The wavelength of the sound in the medium towards the observer decreases.
Due to Doppler effect, the frequency or wavelength of the sound changes towards the observer only.
The actual frequency and wavelength of the source does not change.
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