Question

A whistle emitting a loud sound of frequency 540 Hz is whirled in a horizontal circle of radius 2 m and at a constant angular speed of 15 rad/. The speed of sound is 330 m/. The ratio of the highest to the lowest frequency heard by a listener standing at rest at a large distance from the center of the circle is

(A) 1.0

(B) 1.1

(C) 1.2

(D) 1.4

Answer 1

Correct option (C) 1.2

Explanation:

v1 and v2 are speed of whistle| v1 | = | v2 | = ωr = 15 x 2 = 30 m/sMaximum frequency heard → Here,f → original frequency (540 Hz)v → speed of sound vs→speed of whistle