Question

Two cars are moving on perpendicular roads. When ear-1 sounds a horn of frequency n, then the apparent frequency of sound heard by car-2 is (v is velocity of sound)

• A. $n\left[\frac{V_1+V_2}{V_1-V_2}\right]$
• B. $n\left[\frac{V_1+V_{2}cos{\theta }_2}{V_1-V_{2}cos{\theta }_1}\right]$
• C. $n\left[\frac{Vcos{\theta }_2}{V_{1}cos{\theta }_1}\right]$
• D. $n\left[\frac{V+2V_{2}cos{\theta }_1}{V-2V_{1}cos{\theta }_2}\right]$

Answer 1

The correct option is B $n\left[\frac{V_1+V_{2}cos{\theta }_2}{V_1-V_{2}cos{\theta }_1}\right]$

The apparent frequency of sound heard by car-2 is

$n^{\prime }$ = $n\left[\frac{V_1+V_{2}cos{\theta }_2}{V_1-V_{2}cos{\theta }_1}\right]$