Conditions for hearing echo - class-IX
Description: conditions for hearing echo | |
Number of Questions: 56 | |
Created by: Seema Agrawal | |
Tags: study of sound physics wave motion acoustics waves sound world of sounds |
An echo of the sound produced can be heard only if it reaches our ear after -
We can hear echoes only near the mountains. True or false.
In order to produce an echo, the minimum distance between the source of the sound and the reflecting body should be :
The minimum distance between the source of a sound and reflecting body should be 17 m for the formation of an echo. True or false
The time gap between the two sounds-direct and echo depends upon:
The direct sound and the echo can be heard differently provided:
A room have two walls at a distance of 12 m.
For the production of an echo, size and nature of obstacle should be:
The minimum distance in air between the observer and the obstacle for an echo to be heard clearly at temperatures higher than $25^o$C is:
Echo can be heard if
For the production of an echo, the reflecting surface should be:
A sponge is kept at a distance of 19m from the source of sound then:
Fill in the following blanks with suitable words
(a) An echo is simply a ______ sound.
(b) Pitch of sound depends on __.
(c) Loudness of sound depends on _.
(d) Quality of sound depends on_.
(e) Echoes are caused by the ______ of sound.
In a room two walls are at a distance of 159 m, then
When echo is heard?
An echo is heard on a day when temperature is about $44^0$C. When will the echo be heard if the temperature falls to $80^0$C?
A room have two walls at a distance of 12m :
For the production of an echo,size and nature of the obstacle should be :
In a room two walls are at a distance of 159 m. Then :
A sponge is kept at a distance of 19m from a source of sound.
The minimum distance in air between the observer and the obstacle for an echo to be heard clearly at temperatures higher than ${25}^{0}C$ is :
For the production of an echo, the reflecting surface should be :
The minimum distance between the source of sound and the reflecting surface necessary to cause echo is
The minimum distance to hear a clear echo is (V is the velocity of sound)
A man, standing between two cliffs, claps his hands and starts hearing a series of echoes at intervals of one second. If the speed of sound in air is $340ms^{-1}$, the distance between the cliffs is?
If two consecutive signals with a difference of 0.1 s are incident on a rock, distant 20 m from the source, will we get two echoes
A signal source starts from rest and moves away from a stationary wall with an acceleration of $0.5 m/s^2$. After what time in secs will we hear an echo
A source of sound is kept at a distance of 10 m from a wall. What distance should it be moved further, so that an echo is heard
A source of sound moves with an uniform velocity away from a wall. An echo is heard at 4th second from its beginning position, what is the speed of the source
To hear an echo, the minimum distance between source of sound and reflecting body is 17m.
The minimum distance between the sound and the reflecting surface, in order to hear an echo, must be
Velocity of sound in the atmosphere of a planet is 600m$s^{-1}$. The minimum distance between the source of sound and the obstacle to hear echo should be
A source of sound emitting a tone of frequency 200 Hz moves towards an observer with a velocity v equal to the velocity of sound if the observer also moves away from the source with the same velocity v, the apparent frequency heard by the observer is
A table is revolving on its axis at 5 revolutions per second. A sound source of frequency 1000 Hz is fixed on the table at 70 cm from the axis. The minimum frequency heard by a listener standing at a distance from the table will be (speed of sound = 352 m/s)
A person clapped his hands hear cliff and heard a echo after 5s. The minimum distance of the cliff from the person if the speed of sound is take as 346 m/s
A mas fires a bullet standing between two cliffs. First echo is heard after $3$ seconds and second echo is heard after $5$ seconds. If the velocity of sound is $336m/s$, then the distance between the cliffs is
A rail engine approaches a hill at a speed of $54\ kmph$ whistling a sound of frequency $160\ Hz$. The frequency of echo heard by the engine driver is (velocity of sound in air $335\ ms^{-1})$.
A driver blows the horn when he is at a distance of $1020m$ from a stiff. He hears the echo after $11/2sec$. At what rate is he approaching the cliff. (velocity of sound in air $=340m/s$)
State whether given statement is True or False
A man standing 25 m away from a wall produces a sound and receives the reflected sound.The man will be able to hear a distinct echo.
What should be the minimum distance (in m) between source and reflector in water so that echo is heard distinctly ? (The speed of sound in water $= 1400\; ms^{-1}$)
The speed of sound in air and sea-water are given to be $340\ m/s$ and $1440\ m/s$ respectively. A ship sends a strong signal straight down and detects its echo after $1.5$second. The depth of the sea at that point is
State whether the given statement is True or False :
What should be the minimum distance between the source of sound and the obstacle to hear an echo?
A man beats drum at a certain distance from the mountain. He slowly increases the rate of beating and finds that the echo is not heard distinctly, when the drum beating is at the rate of $40$ per minute. He moves by $80 m$ towards the mountain and finds that the echo is again not heard distinctly when the rate of beating of the drum is $1$ per second. What is the original distance of the man from the mountain?
An echo will be heard if the minimum distance between the source of sound and the obstacle is
The echo will be heard if the original sound reflected by an obstacle reaches our ears after
A man is sitting in Gandhi Park of dimension 6m $\times$ 6m. On the left side of it, there is a building adjoining the park, and on the right side of the park, there is a road adjoining by park. A sound is produced on the road by a diwali bomb :
A girl blew a whistle while standing in front of a cliff. She heard an echo after $4s$. Find the distance of the cliff from the boy if velocity of sound in air is $332m{s}^{-1}$
A boy shouts while standing in front of a hill. He hears an echo after $6s$. If the speed of sound in air is $340 m/s$, what is the distance of the hill from the position of the body?
An echo returns in $3 s$. What is the distance of the reflecting surface from the source?
An echo returned in $3 s$. What is the distance of the reflecting surface from the source, given that the speed of sound is ${ 342ms }^{ -1 }$?
Sound produced by a thunderstorm is heard 10 s after the lightning is seen. The approximate distance of the thunder cloud :
(Given speed of sound $= 340 m s^{1}$)
The ceiling and wall behind the stage of good conference halls or concert halls are made:
What should be the minimum distance between the listener and the reflector to hear an echo of sound propagating with a speed $v\ m s^{-1}$?
A man starts from rest and moves with constant acceleration towards a hill which is $648 m$ away. He fires a gun at the instant of starting and hears its echo after $4$ seconds. Velocity of sound in air is $320 m/s$
A man fires a gun and hears its echo after 5 s. The man then moves 310 m towards the hill and fires his gun again. This time he hears the echo after 3 s. Calculate the speed of sound.