Question

A sound source is moving towards a stationary observer with $\frac{1}{10}$ 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

The correct option is A 10/9

$n^{\prime }=n\left(\frac{v}{v-v_s}\right)=n\left(\frac{v}{v-v/10}\right)\Rightarrow \frac{n^{\prime }}{n}=\frac{10}{9}$