Chapter 15, Problem 4STP

To determine

To Choose:The correct option.

Answer to Problem 4STP

The answer is option C- $\text{538 Hz}$ .

Explanation of Solution

Given data:

Speed of the car is $v_s=60\text{km/h}=16.67\text{ m/s}$ .

Frequency $f$ of the horn is $\text{512Hz}$ .

Speed of sound in air is $v=\text{343 m/s}$ .

  $v_r=0$

Formula used:

Let the frequency of the sound perceived by the observer be $f_d$ , then the formula used is

  $f_d=f\left(\frac{v+v_r}{v-v_s}\right)$

Calculation:

Substituting the given values, we get

  $\begin{array}{l}{\text{f}}_d=\text{512}\left(\frac{343+0}{343-16.67}\right)\\ =538.15\text{ Hz}\\ =538\text{ Hz approx}\text{.}\end{array}$

Conclusion:

Hence, the answer is C- $\text{538 Hz}$ .