Question

6.S1 and S2ate two sound sources of frequencies 338HZ and 342Hzrespectively placed at a large distance apart.The velocity with which an observer should move from s2 to s1 so that he may hear no beats will be ---------(velocity of sound in air=340m/s)

Answer 1

$$\begin{gathered} Actualfrequencyofthefirstsourceis338Hz \\ actualfrequencyofthesecondsourceis342Hz. \\ apparentfrequencyofthesoundwhensourceisatrestandlistnerismovingisatrest. \\ f=\frac{v-v_l}{v}\times f_0 \\ visthevelocityofsound \\ {v}_{l}isthevelocityoflistner \\ forsource{s}_1,listnerismovingtowardsthe{s}_1 \\ {f}_1=\frac{v+v_l}{v}\times 338 \\ forsource{s}_2,listnerismovingawayfromthesource \\ {f}_2=\frac{v-v_l}{v}\times 342 \\ fornobeatfrequency{f}_1-f_2=0 \\ \frac{v+v_l}{v}\times 338-\frac{v-v_l}{v}\times 342=0 \\ \frac{v+v_l}{v}\times 338=\frac{v-v_l}{v}\times 342 \\ {v}_i=170m/s \end{gathered}$$