A car passes a person standing on road, when car was approaching it, frequency received by person was $n$ . When it recedes, the frequency received by the person is $3 n / 5$ , find speed of car. (Speed of sound = $330 m / s$ )

60.4 m/s

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

82.5 m/s

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

32.8 m/s

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

4.34 m/s

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

Open in App

Solution

The correct option is B 82.5 m/s
By using doppler's effect we can say:

When car is approaching the person:
$n = n_{0} {\frac{330 - 0}{330 - x}}$

When car is receding the person:
$\frac{3 n}{5} = n_{0} {\frac{330 - 0}{330 + x}} \frac{n/}{\frac{3 n/}{5}} = \frac{n_{0} (\frac{/ 330}{(330 - x)})}{n_{0} \frac{/ 330}{(330 + x)}} = \frac{330 + x}{330 - x} \Rightarrow \frac{5}{3} = \frac{330 + x}{330 - x}$

$\Rightarrow x = 82.5 m / s$

Suggest Corrections

Similar questions

Q. A car is moving at speed of 54

k m / h r

and produces a sound of frequency 630

H z

. A person running with a speed of

2 m / s

is approaching the car. What frequency would the person hear? (speed of sound =

330 m / s

)

The horn of a car emits sound with a dominant frequency of 2400 Hz. What will be the apparent dominant frequency heard by a person standing on the road in front of the car if the car is approaching at 18.0 km/h ? Speed of sound in air = 340 m/s.

A person riding a car moving at 72 km/h sounds a whistle emitting a wave of frequency 1250 Hz. What frequency will be heard by another person standing an the road (a) in front of the car (b) behind the car ? Speed of sound in air = 340 m/s.

Q. A car approaching a crossing at a speed of

20 m / s

sounds a horn of frequency

500 H z

when

80 m

from the crossing. Speed of sound in air is

330 m / s .

What frequency is heard by an observer

60 m

from the crossing on the straight road which crosses car road at right angles?

Q. A person riding a car moving at 72 km h⁻¹ sound a whistle emitting a wave of frequency 1250 Hz. What frequency will be heard by another person standing on the road (a) in front of the car (b) behind the car? Speed of sound in air = 340 m s⁻¹.

Join BYJU'S Learning Program

A car passes a person standing on road, when car was approaching it, frequency received by person was n. When it recedes, the frequency received by the person is 3n/5, find speed of car. (Speed of sound = 330 m/s)

The correct option is B 82.5 m/sBy using doppler's effect we can say: When car is approaching the person: n=n0{330−0330−x} When car is receding the person: 3n5=n0{330−0330+x}n/3n/5=n0(/330(330−x))n0/330(330+x)=330+x330−x⇒53=330+x330−x ⇒x=82.5 m/s

A car passes a person standing on road, when car was approaching it, frequency received by person was $n$ . When it recedes, the frequency received by the person is $3 n / 5$ , find speed of car. (Speed of sound = $330 m / s$ )