A whistle emitting a steady note of is at rest near a listener

PHYSICS · Subjective · CBSE · Physics · Waves · Waves

Problem

A whistle emitting a steady note of

540\,\text{Hz}

is at rest near a listener. A second whistle of unknown frequency moves straight towards the listener with a speed of

30\,\text{m\,s}^{-1}

through still air (

v_{\text{sound}} = 330\,\text{m\,s}^{-1}

). The listener hears

4

beats per second. Find the two possible values of the frequency of the moving whistle.