Question

A sound source is moving towards a stationary observer with one-tenth of the speed of sound. The ratio of apparent to real frequency is

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

Answer 1

The correct option is C $10/9$

$n^{\prime }=\frac{V}{V-V_s}{n}_0$, here $V_s=\left(1/10\right)V$,

therefore,

$n^{\prime }=\frac{V}{V-\left(1/10\right)V}{n}_0=\left(10/9\right)n_0$.