Reflection of Sound (Physics) 

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

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 .

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 ]

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

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

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🎉🎉

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

This sir was the best teacher, because he explains in English , but the other teachers and RU-vid 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 ❤️

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 😍

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

1 - Yes, sound obeys the laws of reflection. Following are the laws: a -

Best teacher ever

1.yes,

THANKS FOR YOUR EFFORT

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

8 years back If I would have got you like teacher, or these type of study material in my PUC I would have got distinction..... Although I worked hard I couldn't understand these silly topics.. but practically I understood everything now, although it may not help in my studies or career now... Thk u heartly teacher....

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❤️❤️❤️

8:49 watch it looks real that sir goes there

Yes,1)

sir I have loved your teaching style and the vivid examples that you give in your videos

Best teacher in the universe. ....thanks a lot sir

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!

I am from Nigeria I love ur teaching sir I wish I had a teacher like you here

1: yes it does , incident rays = reflected rays 2: beacuse large distance help hear echoes (minimum distance between speaker n reflector should be more than 17 metres ) 3: 1- 51 2- 85( 51 +85=136) Distance between the two hills is 136

Ye 1:yes Laws of sound is Echoes and reverberation 2: To listen echones sound the area will be more then we listen .in small room we can't listen because its area will be less .. 3:Distance=speed*time 1st one =2d=340m/s*0.3s Then 2d=102 D=102/2 D=51m 2one =2d=340*0.5s Then 2d=170 D=170/2 D=85 Then1+2= 51+85 =136

1.yes, angle of incidence is equal to angle of reflection and angle I,angle r and normal lie I'm the same plane 2.Because reflecting surface is smaller than the wavelength of sound wave 3.136 m

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

the legend summarized 30 pages of impossible-to-understand concepts within a few minutes with cristal clear clarity.

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)

1)it obeys and laws of reflection is the reflection of light is equal to angle of incidence. 2)it should be nearly 17m wide room to hear the sound of echo. 3)

Q-1) Yes, the laws of reflection of sound are as follow Incident rays go ang coming ray is reflected ray. Q-2) We cannot hear echoes in a small room because we hear an echo in a distance of 17 metres or more from the reflecting surface / an area because equal distance in the forward reverse is direction. Q-3) Distance = speed × time Therefore, A) 1st D = 340m/s × 0.3s = 102m B) 2nd D = 340m/s × 0.5s = 170 m Total D = 272m

A2: we cannot hear echoes in a small room because the room is so small and time taken by sound to get reflected and reach our ear is less than 0.1 seconds so our ears are not so sensitive to hear it

1) Sound does obey the laws of reflection. The laws of reflection for sound is 1. The angle of incidence is equal to the angle of reflection. 2. The incident sound, reflected sound and normal all lie on the same plane. 2) We can't hear echoes in a small room because echoes need a minimum distance of 17m to produce an echo and a room has a much smaller distance than 17 metres. 3) 34m

Sir. I love the way u are teaching i could understand everything ❤‍🔥❤‍🔥❤‍🔥

You are the best teacher that l had ever seen. The way you are teaching is perfect and easy to understand the concept

1. Yes... the angle of incidence is equal to the angle of reflection and the incident Ray, the normal and the reflected Ray at the same point of incidence all lie on the same plane. 2. We can't hear Echoes in a small room because sound doesn't reflect back. 3. d=51m d=85m. Thank you sir. Your explanation was superb 👌👏👏👍

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

Best teacher ever ☺️😊

You may assist me with these questions; 1. A girl stands 160m away from a high wall and claps her hands at a steady rate so that each clap coincides with the echo of the one before. If she makes 60 claps in one minute, calculate; A) the speed of sound. B) If she moves 40cm closer to the wall, she finds that the clapping rate has to be 80 per minute, calculate the speed of sound.

My best teacher,I'm corresponding student in South Africa and I rely on your videos to learn

U are good teacher I ever seen in my life 😢

Ans 1 Yes, it obeys the laws of reflection. Two laws of reflaction are a. Angle of incidence, reflaction and normal all lie in same plane. b. Angle of reflection is equal to angle of reflection i=r Àns2- we cannot hear the echo sound because of our lower sensitivity of ear and dur to less space. Ans 3- ....

1.Yes and firstly there are 3 laws of reflection which are:- a. Angle of incidence = angle of reflection b. Incident ray, reflected ray and normal lie on same plane c. Incident ray and reflected ray are on the either side of normal 2. The distance of our ear and the wall is less than 17.2 m 3. 136 meter

i love physics thanks for making chapter so easy and another for your top 3 questions truly they are exam oriented and you are my most fav teacher thanks you sir ...

Sir you always teach in a proper and easy way.Thank you for this video.It helped me a lot.

You teaches very well thanks for explaining such an interesting chapter…

1.Yes the sound obeys the laws of reflection. First law-The angle of incidence is equal to the angle of reflection. Second law-the angle of incidence,the angle of reflection and the normal ray all lie in the same plane.

Sir your teaching is very interactive and you mainly show the daily life examples....by using different equipments,toys,models and many more ..... Sir thank u for ur effort for us .. 🙏🙏❤️❤️

Hello sir. I don't lyk physics that much before watching your video. Thank you sir

Hi sir! This link was sent to us by our teacher before the exam. These videos really helped. thank you!!!!!

Q1: yes , sound obey laws of reflection Reflection of sound -insident ray ,it's carrospoing reflected and the normal lay on the same plane Q2: we cannot hear eho in a small room because there are good absorbers of sound . And echo is possible in large area where it contains the reflector of sound

Best channel for physics So simple videos 😊

Sir my all doubt are clear after this video

Sir, you are a future maker.

Thanks.. and great experience.. Recollecting all that I hv studied between 44 & 40 yrs ago.. The audio video facilities wld hv made a great difference in those days..and our generation wld hv been a different altogether.. We had only black & white stereotyped books..

Fantastic lesson. Strong explanations and examples that are easy to understand. My 8 year old was able to answer all of the questions correctly!

Please Sir, help me with the solution to the question below: The speed of sound in air is 330ms-1. How far from the centre of a storm is an observer who hears a thunder clap 2s after the lightning flash? (Neglect the time taken by light to travel to the observer)

Sir your way of explanation was superb

You monsieur, have a knack for explaining stuff! Thanks! :)

my real physics teacher

Really it is very useful for us Very good teaching😃 Thank you so much 🙏🏻🙏🏻🙏🏻

sir you are the best teacher

00:05 This video is about the reflection of sound. 01:40 Sound reflection follows similar laws as light. 03:21 Reflection of sound leads to echo and reverberation. 05:01 Understanding sound reflection in large spaces 06:44 Hill absorbs sound energy resulting in softer second hello. 08:24 Reverberation is the persistence of sound caused by overlapping reflections. 10:04 Balance between sound absorption and reverberation in acoustic engineering 11:39 Absorbers reduce sound reflection in the house

I learn so many things from you... And get many kinds of activities.... Teaching ideas ...thanks alot

Sir your explanation is the best. It helps us a lot please keep teaching. Love you sir.☺️🙂

Thanks for this class

Q1. It obeys The angle of incidence is equal to the angle of reflection Q2. Because there's no enough distance to reflect the sound

Q1: yes,

@monach academy i want to understand refraction of sound... im. not finding ur video on this topic.

U r a really very good teacher

Nicely explained. The concept of reflection of sound is completely clear to me now.

sir 3rd answer is distance=speed.time so, 4d=340m/s x 0.8=272m so d=68m

Sir I didn't know the meaning of bathroom singers... Can you pls make me understand it

The explanation was so nice i liked the video so much and i learned this without any doubt From Taanvi Desai

Sir second answer is: Because of room size, it is small to the sound travels short distance

because minimum distance between us an reflactor must be 17.2 m which is not is small room so we donot hear echoes in small rooms

Good explanation sir, thank you sir this helps me in doing online home works ..

Sir, you should give the velocity of sound or the temperature for the question 3.

Thanks sir, you explain the topics easily than my school teachers. I am using to learn from you in lockdown.

You are the best teacher thanks sir iam now able to answer some questions from this topic

U r a great teacher

Good teaching method .adorable .nice

Thank you for teaching the sound lesson sir

Thank you so much sir for your wonderful teaching

Wowww thanks sir 🔥🔥🔥🔥🔥🙏🙏

Amazing teacher with amazing topic

Sir you teach far better than any other teacher...,✨🤩

1)Yes it does,It's incident Ray is parallel to the Reflected ray and the angle of Incidence is equal to the angle of reflected ray. 2)It is because in a small room the reflected sound distance is not enough which is 17 m

Your service is very useful. Thank you very much sir.

1.yes..it obeys the law of reflection...

very good explanation,easy to understand Thanks

You are genious & excellent teacher.your method of teaching practically is very nice & make the besic concept of each topic of science strong .

Is the 3rd ans 136m ?

(Answer of Q1) Yes, sound obeys the laws of reflection. Laws of reflection of sound --- (i) Angle of incidence=angle of reflection. (ii) incident sound, reflected sound and the normal lie on the the same plane. (Answer of Q2) For hearing echoes, the minimum distance between the speaker and the reflecting surface should be 17m. In small rooms, the distance is less than 17m and hence, we cannot hear echoes in small rooms. (Answer of Q3) Distance=speed X time The distance between the man and the 1st hill=(340m/s X 0.3s)/2 =51m The distance between the man and the 2nd hill=(340m/s X .5s)/2 =85m So the total distance between the two hills=(51+85)m=136m.

Angle of incidence = angle of reflection and both of them line in the same 2d plane Because the distance is less than 17 meters Distance d1 is 51 meters and d2 is 85 meters from the man standing, so the distance between the two hills is 136 meters

1st- it obeys 2nd-For an echo, a room needs to be at least 17m 3rd- and 136m

Sir I have a doubt when I shout in my balcony there is a echo outside but there are walls near me to. How is that?

You are the supper I am very attractive by your teaching method

You are the best teacher I ever seen thanks

Excellent presentation for difficult questions.