A source of sound whose frequency is 1000 tex | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) The frequency of the sound waves reflected by the fixed obstacle, as received by the obstacle, is given by the Doppler effect formula for a moving

Vedclass · Accepted Answer

$1.2$

Vedclass · Answer

(C) The frequency of the sound waves reflected by the fixed obstacle, as received by the obstacle, is given by the Doppler effect formula for a moving source and stationary observer: $f_1 = f \left( \frac{v}{v - v_s} ight)$ Substituting the values: $f_1 = 1000 \left( \frac{330}{330 - 33} ight) = \frac{1000 	imes 330}{297} 	ext{ Hz}$. Now, the reflected waves act as a source (stationary) and the receiver (moving with the source) acts as an observer moving towards the reflected waves: $f_2 = f_1 \left( \frac{v + v_D}{v} ight)$ Substituting $f_1$: $f_2 = \left( \frac{1000 	imes 330}{297} ight) \left( \frac{330 + 33}{330} ight) = \frac{1000 	imes 363}{297} 	ext{ Hz}$. $f_2 = 1000 	imes 1.2 = 1200 	ext{ Hz} = 1.2 	ext{ kHz}$.

Similar Questions

$A$ boy standing on a platform observes the frequency of a train horn as it passes by. The change in the frequency noticed as the train approaches and recedes him with a velocity of $108 \text{ km/h}$ is (speed of sound in air $= 330 \text{ m/s}$) (in $\%$)

$A$ man sitting in a moving train hears the whistle of the engine. The frequency of the whistle is $600 \ Hz$.

Vedclass Test Series

Exam Paper Generator

Online Exam Module