Question

A sound source is moving towards a stationary observer with 1/10 of the speed of sound. The ratio of apparent to real frequency is

• A. 10/9
• B. 11/10
• C. $(11/10)^{2}$
• D. $(9/10)^{2}$

Answer 1

Answer: (A)

10/9

Answer 2

$n' = n\left( \frac{v}{v - v_{S}} \right) = n\left( \frac{v}{v - v/10} \right)$⇒ $\frac{n'}{n} = \frac{10}{9}$