What should be the velocity of a source of sound so that the apparent frequency to a listener will be half the actual frequency of the source? Velocity of sound in air = v .

What should be the velocity of a source of sound so that the apparent

1.	What should be the velocity of a source of sound so that the apparent frequency to a listener will be half the actual frequency of the source? Velocity of sound in air = v .
Answer» Solution :If n is the actual frequency , APPARENT frequency ` = n/2` Here the listener is stationary, i.e., ` u_(o) = 0 ` Again decrease of frequency means that the source is RECEDING from the listener . So the velocity of the source ` u_(s) ` is negative Therefore, from the relation ` n. = (v + u_(0))/( v - u_(s))xx n ` , we have , ` n/2 = (v)/(v + u_(s)) xx n " or " , v + u_(s) = 2V " or " , u_(s) = v ` i.e., the source is receding from the listener with the velocityof sound .