A sound source, emitting sound of constant frequency, moves with a constant speed and crosses a stationary observer. The frequency \(n\) of sound heard by the observer is plotted against time \(t\). Which of the following graphs represents the correct variation?
A source of sound is moving away from a stationary observer with constant velocity 40 m/s. Find frequency heard by observer, if original frequency of source is 400 Hz and speed of sound in air is 360 m/s