Figure (16-E12) shows a source of sound moving along the X-axis at a speed of 22 m s continuously emitting a sound of frequency 2-0 kHz which travels in air at a speed of 330 m s-1. A listener Q stands on the Y-axis at a distance of 330 m from the origin. At t = 0, the source crosses the origin P. (a) When does the sound emitted from the source at P reach the listener Q? (b) What will be the frequency heard by the listener at this instant? (c) Where will the source be at this instant?


(a) Speed of the sound is 330 m/s and the distance from P to Q is 330 m.


So, the time needed will be,



(b)


The direction of the source is perpendicular to the direction of listener. As, there won’t be any change in the actual frequency.


(c)


The speed of the source is 22m/s and it took 1s. So the distance traveled will also be 22m. Hence, it will be at x=22m


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