You visited us 1 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard XII

Physics

Source and Listener Moving in Different Lines

A source of s...

Question

A source of sound S is travelling at $\frac{100}{3} m / s$ along a road, towards a point A. When the source is 3 m away from A, a person standing at a point O on a road perpendicular to AS hears a sound of frequency v’. The distance of O from A at that time is 4m. If the original frequency is 640 Hz, then the value of v’ is (velocity of sound is 340 m/s)

620 Hz

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

680 Hz

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

720 Hz

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

840 Hz

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

Open in App

Solution

The correct option is B 680 Hz
Effective value of velocity of source is

$v_{s} = \frac{100}{3} c o s θ$
$= \frac{100}{3} \times \frac{3}{5} = 20 m / s$
$v^{'} = \frac{v}{v - v_{s}} v$
$v^{'} = \frac{340}{340 - 20} \times 640 H z = 680 H z$

Suggest Corrections

Similar questions

Q. A source of sound is travelling at

\frac{100}{3} m / s

along a road, towards a point A. When the source is

3 m

away from A, a person standing at a point O on a road perpendicular to the track hears a sound of frequency

f

. The distance of O from A at that time is

4 m

. If the original frequency is

640 H z

, then the value of

f

is (given velocity of sound =

340 m / s

)

A source of sound is traveling at

\frac{100}{3} m s^{- 1}

along a road, towards a point A. When the source is 3 m away from A, a person standing at a point O on a road perpendicular to the track hears a sound of frequency v'. The distance of O from A at that time is 4 m . If the original frequency is 640 Hz, then the value of v' is :

(Given velocity of sound =

340 m s^{- 1}

)

Q. A source of sound of frequency 640 Hz is moving at a velocity of

\frac{100}{3}

m/s along a road, and is at an instant

30 m

away from a point A on the road (as shown in figure). A person standing at O,

40 m

away from the road hears sound of apparent frequency

ν^{'}

. The value of

ν^{'}

is:
(velocity of sound =

340 m / s

)

Q. A sound source

S

is moving along a straight track with speed

v,

and is emitting sound of frequency

ν_{0}

(see figure). An observer is standing at a finite distance, at the point

O

, from the track. The time variation of frequency heard by the observer is best represented by:
(

t_{o}

represents the instant when the distance between the source and observer is minimum)

Q. A source of sound

S

moving with constant speed approaches a junction

A

. If the original frequency produced by the source is

640 Hz

then for the situation shown in the figure, the apparent frequency heard by the observer at rest at

O

will be
[speed of sound

= 340 m/s

]

Join BYJU'S Learning Program

The correct option is B 680 HzEffective value of velocity of source is vs=1003 cosθ =1003×35=20 m/s v′=vv−vsv v′=340340−20×640 Hz=680 Hz

The correct option is B 680 Hz
Effective value of velocity of source is

$v_{s} = \frac{100}{3} c o s θ$
$= \frac{100}{3} \times \frac{3}{5} = 20 m / s$
$v^{'} = \frac{v}{v - v_{s}} v$
$v^{'} = \frac{340}{340 - 20} \times 640 H z = 680 H z$