Reflection of Sound (Physics)

What is reflection of sound? What is echo and reverberation? Watch this video to learn more! We have compared the reflection of sound with the reflection of light. Echoes and reverberations are discussed in detail. Try the Top 3 Questions at the end of the video and write your answers & doubts in the comments below!

[abdul-majeedyakubu]

Q1. Yes.
The laws of reflection of sound are.
1. The incident angle is equal to the reflected angle.
2. The incident ray the reflected ray and the normal ray all lie on the same plane.
Q2
Because the room is small.
Q3.
Distance=speed X time.
First echo distance.
2d=340m/s X 0.3s
2d=102
d =51m
Second echo distance
2d=340m/s X 0.5
2d=170
d=85m.
Total distance=51m + 85m
Total distance=136m

[mathangiaditya]

1 st question answer : Yes .
Angle of incidence is equal to angle of reflection .
2 nd que answer : Because there are a few good absorbers in our room to absorb sound like, curtains .
3 rd que answer : 1 ; distance = speed * time
2d = 340 m/s * 0.3
2d = 102 m
d = 102 / 2
= 51 m
2 ; 2d = 340 * 0.5
2d = 170
d = 170/2
d = 85 m
So, 51 + 85 = 136 metres is the distance between the two hills .

[zunairarashed]

1. Yes, it does. The laws are stated below
1st law: the incident angle of sound= reflected angle of sound.
2nd law: the incident sound, normal and the reflected sound lie on the same plane

2. Because of insufficient distance echoes can't be heard in small room. We can differenciate between two sound if the time interval between two sounds is 0.1 second. But in a small distance, the sound reflected takes time less than 0.1 sedond. For this we can't differenciate between two sound and can't hear echoes in a small room.

3. Here, for first hill,
V= 340 m/s
T= 0.3 seconds
2d= vt
Or, 2d= 340× 0.3
Or, 2d= 102
Or, d= 102/ 2
Or, d= 51


Here, for second hill,
V= 340 m/s
T= 0.5 seconds
2d= vt
Or, 2d= 340×0.5
Or, 2d= 170
Or, d= 170/ 2
Or, d= 85

Therefore, total= (85+51) = 136 [ Ans ]

[m.vinayagamjeevath]

Q01. Yes
The laws of reflection are :
1.The incident ray, the normal drawn at the point of incidence and the reflected ray all lie on the same plane.
2.The angle of incidence is equal to the angle of reflection.
Q02. We cannot hear echoes in a small room because the persistence of sound of human ear is 0.1 seconds . In a small room, since the distance travelled by the sound wave is less it is reflected back and reaches the human ear within 0.1 seconds. Thus, the reflected sound cannot be heard distinctly and it's not an echo.
Q03.
Distance=speed X time.
First echo distance.
2d=340m/s X 0.3s
2d=102
d =51m
Second echo distance
2d=340m/s X 0.5
2d=170
d=85m.
Total distance=51m + 85m
Total distance=136m

[SrijitaSahaOfficial]

1. Yes, it does.
The laws of reflection are:
i. The incident ray is equal to the reflected ray.
ii. The normal, incident ray, reflected ray drawn at the point of incidence lie on the same plane.

2. In small rooms,
The distance between dource and reflecting surface is not 17m but smaller than that. Due to which echo is not heard in these small places.

3. 1st echo:
T=0.3s
D=2d
S≈340m/s
340=2d×10/3
D=51 m
2nd echo,
D=2d
T=0.5s
S≈340 m/s
340=2d×10/5
D=85 m
Total distance =51+85
=136 m

[sirpi]

Hw answers: 1 i) angle of incidence is equal to the angle of reflection i= r
ii) Incident ray, normal and reflected ray all lie in the same plane
2) we cannot hear echoes in a small room because the size of reflector must be large
3) distance between the two hills is 136m
Lovely session ever seen 😍

[addictionforphysics]

Third question answer is 136 because

The man standing between two heals and the man fire the bullet and the sound is reflected from both the hills then

Distance traveled 2d at 0.3s
Distance =speed * time
2d= 340 * 0.3=51

Distance =speed *time
2d=340*0.5=85
Add both distance
85+51=136🎉🎉

[clashbaba]

Sir I'm glad to tell you that I pass my science exam with 78/80 and 79/80 in maths!! Just because of your constant efforts! Thank you sir!

[bhaskardebnath]

1. Yes, sound obey the laws of reflection, they are -
The incident ray angle is equal to the reflected ray angle
The normal, ray of incidence and ray of reflection all lie on the same plane

2. Our ears need some delay before the sound echo can be heard again, that's why in small spaces, as the sound echoes too quickly, it cannot be heard by the ears

3. 1st echo -
T = 0.3s
D = 2d
S = 340m/s
340 = 2×10/3
D = 51m
2nd echo -
D = 85m
Total distance = 51+85 = 136m

[powerofmind]

1.yes! Why not sound also obey the law of reflection because sound also have same angle of incident and reflected sound having same angle and another on same plane.
2.we cannot hear sound in small room due to small distance between source and reflecting surface i.e less than 17m or may be curtains and dull surfaces which absorb sound energy.
3.As we know that.
S=v∆t/2
By putting values we get .
343×3/2
=514m.
Another we put
343×5/2
=814m
Combined we get .
514+814
=1328m
Ok sir

[amitabhabhattacharyya]

Sir... U explain us all concerned topics of Sound in a very lucid way n lively ...really praiseworthy..
Thanx a lot..
Regards 🙏

[DamilareJoseph]

Yes, 1)<i=<r
2) incident sounds, reflected sounds, and normal lies in the same plane

3) 2d=(0.5 - 0.3) × 340

2d= 68
d=34m

[BizzBooms]

1 - Yes, sound obeys the laws of reflection. Following are the laws:
a - <i = <r
b - angle of incidence, angle of reflection and normal lie on the same plane

2 - Small rooms consist of small walls. Just to recap, the larger and harder a surface, the easier it is for sound to get reflected. If the surfaces of the walls are small, the chances of sounds to reflect multiple times are lesser. Furthermore, sounds easily reflect in empty rooms but since rooms usually contain sound absorbent materials it gets even more difficult to reflect sound.

3 - distance = speed x time
I'm not sure about this one

[roshnib]

1.yes, <i=<r
incident sound, reflected sound and normal lie on same plane
2. minimum distance between source and reflector must be 17 m.
3. 34*3=102, 102/2=51
34*5=170, 170/2=85
85+51=136m

[georgemichael]

Qn 01. YES it obey...
Qn 02. For an echo to occur, it needs at least 17m from an obstacle to listener.
Qn 03. The answer is 136 m, (I took velocity of sound in air as 340 m/s)

[AastabolProductions]

I'm doing sound engineering. Your videos are helping me a lot. Thank you sir ❤🙏

[mamtapadhy]

Ur English is so simple And easy! Easy to understand and I remembered it well too! BEST TEACHER EVER! U teach really Good Man!

[allnonechannelchannel.]

This sir was the best teacher, because he explains in English, but the other teachers and YouTube channels think they are the best teachers 🙄, but they can't even explain it in English. I kept so many comments in live chat but they are acting that they are not seen my comments 🙄🙄🙄. So you are my best teacher ❤️

[learnwithg.k.s.]

Excellent video
Answers are
1. Yes, Laws of reflection of sound are
a. Angle of incident of sound is equal to angle of reflection of sound.
b. Normal, angle of reflection of Sound and angle of incident of Sound lie on the same plane.
2.We cannot hear the echoes in a small room because the area of a room must be large for echoes to be produced

[quizforyou]

1)Yes, sound obey the law of reflection
That is angle of incidence=angle of reflection.
2)room is a small place. The minimum time gap to hear echoes (0.1s). And in room curtains, carpets, and other objects absorb the sound.
3)1st hill=56m
2nd hill=85m
So, distance between two hills=136m
Thank you a lot sir❤️❤️❤️