A statinary observer receives a sound of frequency 2000 Hz. The variation of apparent frequency and time is shown. Find the speed of source, if velocity of sound is `300(m)/(s)`

Options

A. `66.6(m)/(s)`
B. `33.3(m)/(s)`
C. `27.3(m)/(s)`
D. `59.3(m)/(s)`

Answer

B

Explanation

for AP, `f=f_0((V)/(V-V_Scostheta))`
for PB, `f=f_0((V)/(V+V_Scostheta))`
`f_(min)=1800=f_0((V)/(V+V_S))=2000((V)/(V+V_S))`
`f_(max)=2250=f_0((V)/(V-V_S))=2000((V)/(V-V_S))`
On solving `=33.3(m)/(s)`