An observer is moving away from a sound source of frequency 100Hz. If the observer is moving with a velocity 49m/s and the speed of sound in air is 330m/s, the observed frequency is :

85 Hz

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

91 Hz

No worries! We‘ve got your back. Try BYJU‘S free classes today!

100 Hz

No worries! We‘ve got your back. Try BYJU‘S free classes today!

149 Hz

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is B 85 Hz
Given :
$V_{0} = 49 m / s$
$δ = 100 H z$
$V = 330 m / s$
$V_{δ} = 0 m / s$
By doppler effect formula:
$δ^{1} = δ (\frac{V - V_{0}}{V - V_{s}})$
$= 100 (\frac{330 - 49}{330})$
$= 100 \times \frac{281}{330}$
$= 85 H z$

Suggest Corrections

Similar questions

Q. A source and an observer move away from each other with a velocity of 10 m/s with respect to ground. If the observer finds the frequency of sound coming from the source as 1950 Hz, then actual frequency of the source is (velocity of sound in air = 340 m/s)

A source of sound which is emitting a sound of frequency 600 Hz is moving towards a wall with a velocity of 30 m/s. Three observes A, B, C are taken into consideration. A and B are moving with velocity 20 m/s, 'A' away from the wall and 'B' towards the wall. Here, C is inside the source. Velocity of sound in air is 330 m/s. Then,

Q. A sound source S emitting waves of frequency

100 Hz

and an observer O are located at some distance from each other. The source is moving with a speed,

V_{S} = 19.4 {ms}^{- 1}

at an angle of

60^{\circ}

with line joining the source and the observe as shown in the figure. If the observer is at rest, the apparent frequency observed by the observer is
(Velocity of sound in air

330 {ms}^{- 1})

Q. A source of sound S is moving with a velocity of 50 m/s towards a stationary observer. The observer measures the frequency of the source as 1000 Hz. What will be the apparent frequency of the source when it is moving away from the observer after crossing him ?
(Take velocity of sound in air is

350 m / s

)

A sound source of frequency 600 Hz is moving towards an observer with velocity 20m/s. The speed of sound is 340m/s. The frequency heard by observer will be

Join BYJU'S Learning Program

An observer is moving away from a sound source of frequency 100Hz. If the observer is moving with a velocity 49m/s and the speed of sound in air is 330m/s, the observed frequency is :

The correct option is B 85 HzGiven :V0=49 m/sδ=100 HzV=330 m/sVδ=0 m/sBy doppler effect formula:δ1=δ(V−V0V−Vs) =100(330−49330) =100×281330 =85 Hz

The correct option is B 85 Hz
Given :
$V_{0} = 49 m / s$
$δ = 100 H z$
$V = 330 m / s$
$V_{δ} = 0 m / s$
By doppler effect formula:
$δ^{1} = δ (\frac{V - V_{0}}{V - V_{s}})$
$= 100 (\frac{330 - 49}{330})$
$= 100 \times \frac{281}{330}$
$= 85 H z$