Question

A source and listener are both moving towards each other with speed v/10 where v is the speed of sound. If the frequency of the note emitted by the source is f, the frequency heard by the listener would be nearly

• A. 1.11 f
• B. 1.22 f
• C. f
• D. 1.27 f

Answer 1

Answer: (B)

1.22 f

Answer 2

$n' = \left( \frac{v + v_{L}}{v - v_{s}} \right)n$ ⇒ $n' = \left( \frac{v + \frac{v}{10}}{v - \frac{v}{10}} \right)n$ ⇒$n' = \frac{11}{9}f$ = 1.22 f.