A vehicle with horn of frequency upsilon is moving with a velocity of 30 m/s in a direction perpendicular to the line joining the observer and the vehicle. The observer perceives the sound to have a frequency (v+v1) . If the sound velocity in air is 300 m/s, then.

Question

A vehicle with horn of frequency upsilon is moving with a velocity of 30 m/s in a direction perpendicular to the line joining the observer and the vehicle. The observer perceives the sound to have a frequency (v+v1) . If the sound velocity in air is 300 m/s, then. (A)  v1=0  (B)  v1=0.1 v  (C)  v1=-0.1 v  (D)  v1=10 v

Tardigrade Admin · Accepted Answer

Given: Actual frequency of horn =v Apparent frequency perceived by observer v=v+v1 Velocity of vehicle vs=30 m / s Velocity of sound in air v=300 m / s Doppler's effect of sound is valid only if source and observer are both in relative motion. As the source is moving in a direction perpendicular to the straight line which joins the observer hence, there is no relative motion between them. Therefore, Doppler's effect will not occur. Thus, v1 = 0

Q. A vehicle with horn of frequency $υ$ is moving with a velocity of $30 m / s$ in a direction perpendicular to the line joining the observer and the vehicle. The observer perceives the sound to have a frequency $(v + v_{1})$ . If the sound velocity in air is $300 m / s$ , then.

$v_{1} = 0$

$v_{1} = 0.1 v$

$v_{1} = - 0.1 v$

$v_{1} = 10 v$

Q. A vehicle with horn of frequency υ is moving with a velocity of 30m/s in a direction perpendicular to the line joining the observer and the vehicle. The observer perceives the sound to have a frequency (v+v1​) . If the sound velocity in air is 300m/s, then.

v1​=0

v1​=0.1v

v1​=−0.1v

v1​=10v

Q. A vehicle with horn of frequency $υ$ is moving with a velocity of $30 m / s$ in a direction perpendicular to the line joining the observer and the vehicle. The observer perceives the sound to have a frequency $(v + v_{1})$ . If the sound velocity in air is $300 m / s$ , then.

$v_{1} = 0$

$v_{1} = 0.1 v$

$v_{1} = - 0.1 v$

$v_{1} = 10 v$