Echo

Q. What is the minimum distance required To produce distance echo is

Q. The repetition of sound caused by the reflection of sound wave is called Echo.

1. True
2. False

Q.

How do echoes in a normal room affect the quality of the sounds we hear?

Q. Give an example of how diffused reflection can be useful.

Q.

Why will an echo not be heard when the distance between the source of sound and the reflecting surface is $10m$?

Q. Answer the following questions.A. define the term echof. B why do we not here he echoes in ordinary surroundings.

Q.

For a sound wave, angle of reflection is always______angle of incidence.

1. less than

2. greater than

3. equal to

4. twice the

Q. Why doesn't it echo in a well furnished house?

Q.

Why does sound get reflect only after a certain distance ?that is 17m this point are also called eco point .

Why does eco (sound reflect)after 17m? Not in short distance?

Q. What is sound echo and how is it created ? Why does it happens only in few places and not everywhere ?

Q. Q.1) A person standing at a point 12 m from a wall that produces an echo will not hear it. Give reason

Q. To hear the echo in 1 second , the minimum dis†an ce of source from the reflecting surface should be how much

Q.

An echo of the sound produced can be heard only if it reaches our ear after

1. 1/15th of a second

2. 1/13th of a second

3. 1/10th of a second

4. 1/5th of a second

Q.

Echo is produced due to

1. reflection of sound

2. refraction of sound

3. resonance

4. none of these

Q. The minimum time difference to get an echo

Q.

Sounds travel through all (solid liquid has) then why does we hear eco? Why does it occurs at particular distance?

Q.

What is echo???

Q.

What is echo?

Q. Echo cannot be heard in a small room.

1. True
2. False

Q. What is a Echo \vert What are its uses

Q. In a big hall, the sound gets reflected inside the hall multiple times.This phenomenon can be observed in:

1. Auditoriums
2. Cinema halls
3. Indoor stadiums
4. Vacuum chamber

Q.

What is an echo? What is the condition in order to hear an echo.

Q. Why will we get resound in some areas?

Q. To hear an echo, time interval between the original sound and the echo is ___.

1. less than 0.05 s
2. 0.05 s
3. more than 0.1 s
4. less than 0.1 s

Q. A road runs midway between two parallel rows of buildings. A motorist moving with a speed of $36km{h}^{-1}$ sounds the horn. He hears the first echo one second after he has sounded the horn. Speed of sound in air is $330m{s}^{-1}$ . Then The distance between the two buildings and the time after which he hears second echo are

1. 300.2m, 1.5 s
2. 360 m, 2.3 s
3. 329.8 m, 2s
4. 350 m, 2.5 s

Q. If a child hears an echo from a cliff 6 second after the sound produced by shouting, how far is the cliff?

1. 58 m
2. 1030 m
3. 68 m
4. 990 m

Q.

A person is standing at a distance of '$d$' m from a wall and clapping at a rate of $4$ claps per second. The echo of his clap coincides with his clap and he hears the echo of two claps after he stops clapping. What is 'd'? (Assume velocity of sound to be $340m{s}^{-1}$)

1. $150m$

2. $75m$

3. $85m$

4. $70m$

Q.

Give scientific reasons:

An echo is not heard in a small room but it can be heard in hills near ravines.

Q. If a house is not filled with objects like, cushions, curtains etc. There is a echo or a reverberation

Q. $T_1,T_2,T_3$ be the reverberation times for an empty auditorium, when the hall has wounded curtains, and when curtains are made to unwound respectively. Arrange the reverberation times in ascending order.

1. $T_1,T_2,T_3$
2. $T_3,T_2,T_1$
3. $T_1,T_3,T_2$
4. $T_2,T_3,T_1$