Wave Motion Ques 87
- A bus is moving towards a huge wall with a velocity of $5 ms^{-1}$. The driver sounds a horn of frequency $200 Hz$. The frequency of the beats heard by a passenger of the bus will be ….. Hz. (Speed of sound in air $=342 ms^{-1}$ )
(1992, 2M)
Show Answer
Answer:
Correct Answer: 87.6
Solution:
Formula:
- Frequency of refracted sound
$$ \begin{gathered} f^{\prime}=f\left(\frac{v+v_o}{v-v_s}\right)=200\left(\frac{342+5}{342-5}\right) Hz=205.93 Hz \end{gathered} $$
$\therefore$ Beat frequency $=f^{\prime}-f=(205.93-200)$
$$ =5.93 Hz \simeq 6 Hz $$
BETA
