To everyone who's studying Checklist: • A bottle of water, at least 1liter. Your brain works better if it has enough water and drinking helps you to concentrate • Your charger. You sometimes don't even notice that your device's battery is going down, so better have it plugged in all the time • Your headphones. You will be able to focus more with headphones, because it blocks background noises. Also, if it's a late night study session, you won't wake up anyone • a tea or coffee. Coffee keeps you awake, green or black tea can make you feel more awake as well. • Your study/work stuff: your laptop/tablet/phone , a few pens, paper or whatever you need. •Anything else you could need, what about a heat pad, a blanket, a good lamp, your pet so you have a study buddy Reminder:After an hour, you should stand up and walk a bit around. Better stop the music or put on different music for the break. Open your window, even if it's cold outside. Fresh air will make it better, trust me. You could also lay your head down on your desk for ten minutes and listen to a podcast. Or, if you have to read a book, listen to the audiobook of it. You can also listen to the audiobook while doing another thing, that's even better than listening to music while reading the book. I hope y'all had a good day, if not, that's okay too. Remember to take care of yourself and try to get some sleep tonight
Timestamps 00:04 - Introduction to key types of motion in physics. 00:47 - Lecture delayed but relevant for upcoming exams. 02:12 - Overview of Sound and Wave Motion in Class 9 Science. 03:00 - Understanding translational motion in physics. 04:14 - Understanding rotary and vibrational motion related to sound. 04:56 - Understanding the motion of particles in waves and vibrations. 07:15 - Understanding vibration through a spring-block system. 08:40 - वाइब्रेशन का साउंड में महत्व और मूल विचार 09:21 - Understanding sound requires knowledge of vibrations and waves. 10:58 - Wave motion causes particles to vibrate and transfer energy. 11:42 - Energy transfer involves vibrations and particle motion. 13:08 - Waves disturb particles in a medium during their motion. 13:54 - The difference between particle motion and wave motion is explained. 15:39 - Introduction to sound and wave motion concepts. 16:34 - Introduction to sound and wave types in Class 9 Science. 18:04 - Understanding longitudinal and transverse waves in particle motion. 18:56 - Slinky demonstrations reveal sound wave propagation concepts. 20:24 - Energy is transmitted through waves, disturbances in a medium. 21:45 - Longitudinal waves vibrate particles along the direction of wave motion. 23:33 - Water appears to move, but nothing is actually advancing. 24:20 - Understanding the effects of touching a leaf on water. 25:45 - Water does not flow without a potential difference. 26:31 - Sound waves exhibit oscillatory motion in different directions. 28:06 - Explains how particle movement affects each other when seated or standing. 28:45 - Experiment illustrating synchronization through standing and sitting movements. 30:16 - Understanding vibrations and transverse waves in sound. 31:31 - Understanding right angles and wave-particle vibrations. 33:13 - Understanding forces and waves without particles. 33:56 - Sound requires a medium to travel, unlike some waves. 36:11 - Sound is a mechanical wave requiring a medium for propagation. 37:07 - Sound waves require a medium; unlike electromagnetic waves, they don't. 38:34 - Introduction to sound and its production process. 39:21 - Sound is produced by vibrations from a source. 40:41 - वाइब्रेशन से साउंड उत्पन्न होता है और कणों का गतिशीलता का प्रदर्शन होता है। 41:36 - Sound is created by the movement of air particles. 43:01 - Sound is a longitudinal mechanical wave requiring particles for propagation. 43:57 - Sound requires medium and collision for production. 46:10 - Vibrations lead to sound wave propagation. 47:06 - Propagation of sound can be visualized using a guitar string analogy. 48:28 - Sound is created by the movement of particles and pressure variations. 49:13 - High and low-pressure regions create sound via compression and rarefaction. 51:41 - Understanding pressure variations through a distance-pressure graph. 52:42 - Understanding depression and troughs in longitudinal waves. 54:15 - Sound travels through longitudinal waves with specific particle movements. 55:08 - Sound requires a medium for propagation. 56:49 - Decreasing air pressure reduces sound intensity in bells. 57:35 - Sound requires a medium for propagation. 59:15 - Understanding wave properties and wavelength in sound. 1:00:01 - Wavelength is the distance between two adjacent crests or troughs. 1:01:42 - Understanding wavelength and frequency in sound. 1:02:31 - Understanding frequency in sound waves and its SI unit. 1:04:22 - Sound wave properties include frequency and tperiod 1:05:12 - Understanding period in wave motion. 1:07:01 - Frequency and period are inversely proportional. 1:07:47 - Understanding amplitude as displacement in vibrations. 1:09:26 - Understanding amplitude and sound wave characteristics. 1:10:27 - Waves are characterized by parameters affecting their distance traveled. 1:12:10 - Understanding wave velocity with its formula and components. 1:13:15 - Understanding the speed of sound in different mediums 1:15:02 - Sound travels at different speeds in solids, liquids, and gases. 1:15:51 - Speed of sound varies but is approximately 330-346 m/s. 1:17:25 - Pitch relates directly to frequency in sound. 1:18:35 - Sound properties depend on pitch and loudness factors. 1:19:58 - Timber refers to the quality of sound in different instruments. 1:20:42 - Different sounds arise from various materials, highlighting the concept of timbre. 1:22:01 - Sound intensity affects how we perceive loudness. 1:22:44 - Sound intensity can damage eardrums from loud sources. 1:24:23 - Reflection of sound depends on surface texture. 1:25:04 - Incident waves of sound interact with surfaces. 1:26:29 - साउंड रिफ्लेक्शन के लिए इन लॉज को समझना जरूरी है। 1:27:15 - Sound travels in a straight line and can be reflected properly. 1:28:36 - Echo occurs in closed spaces, unlike open areas. 1:29:24 - Echo occurs when sound reflects multiple times off surfaces. 1:30:57 - Sound persistence in a closed auditorium is due to repeated reflections. 1:31:42 - Understanding sound communication in everyday scenarios. 1:33:00 - Explains changes in audio quality over time in video production. 1:33:36 - Video quality and sound improvements over the years. 1:34:51 - Sound absorption properties of soft and hard materials. 1:35:33 - Methods to reduce reverberation in sound environments. 1:36:56 - Understanding the functioning of a stethoscope in sound detection. 1:37:37 - Understanding megaphone mechanics and sound direction. 1:39:06 - Sound energy is optimized through concave structures for effective reach. 1:40:02 - Surface shapes influence sound direction and clarity. 1:41:20 - Humans can hear frequencies between 20 Hz and 20,000 Hz. 1:42:15 - Sound is categorized into ultrasound and infrasound based on frequency ranges. 1:44:06 - Infrasound is not audible to humans but detected by animals. 1:44:59 - Human hearing range decreases with age and exposure. 1:46:37 - Ultrasound easily penetrates various materials due to its high frequency. 1:47:23 - Ultrasound applications include imaging for heart diagnostics. 1:48:38 - Ultrasonography uses sound waves to create images of internal organs. 1:49:20 - Ultrasound technology is crucial for monitoring and treating various health conditions. 1:50:36 - Ultrasound is effective for cleaning and detecting defects in electronic components and structures. 1:51:14 - Ultrasonic technology is used to detect underground leaks efficiently. 1:52:32 - Physics plays a critical role in detecting underwater threats. 1:53:17 - Ultrasound helps in navigation and hunting by echo location. 1:54:36 - Calculating wavelength using frequency and speed of sound. 1:55:33 - Sound waves take 3 seconds to travel and return. 1:57:19 - Understanding speed, distance, and time calculations. 1:58:04 - Understanding time and unit conversions in sound wave calculations. 1:59:48 - Sound travels at a speed of 700 meters per second. 2:01:05 - Importance of taking self-notes for effective learning. 2:02:36 - Encouragement for students to excel in Class 9 and transition to Class 10. 2:03:19 - Wrap-up of the class with farewell greetings.
Please solve these two questions ❓...... ❤ Que:-. Write the coordinates of a point on x-axis at a distance of 4 units from origin in the positive direction of x-axis and then justify your answer. -------And------- Que:-. Two coins are tossed simultaneously 500 times. If we get two heads 100 times, one head 270 times and no head 130 times, then find the probability of getting one or more than one head. Give reasons to your answer also.
Good Evening Sir, at 1:00:37 I informedyou correctly sir, please check the answer permeability of a ferromagnetic material decreases as the magnetizing field increases @rakshaksir
@@DevanshPandey-mc9du kafi easy concept hote hai 9th mein.... favourite subject tha mera physics bilkul bhi hard nhi single formula se chapter khatam isliye....for me 9th class sabse easy class thi
Good Evening Sir in the new recent video on the UA-cam Channel of NCERT WALLAH at 1:00:37 I was right about the answer of the question please check about it. Thank You
📕 Sprint Batch for Class 9: physicswallah.onelink.me/ZAZB/4ftf9rrg
Hii
Most awaited chapter sir✊️
Pranam sir ❤❤
Sir aap pe nahi class show hi nahi raha
Sir merathon kab start honge ? I am student of NEEV 2025 batch ...
Sound cleared 🔥🔥
All the Best for your Final Exams ❤❤
👇
R - Reliable
A - Admirable
K - Knowledgeable
S - Supportive
H - Helpfull
A - Amazing
K - kind and some time kindless (i mean rude)😅
😂😊😊❤❤
😂😂
To everyone who's studying
Checklist:
• A bottle of water, at least 1liter. Your brain works better if it has enough water and drinking helps you to concentrate
• Your charger. You sometimes don't even notice that your device's battery is going down, so better have it plugged in all the time
• Your headphones. You will be able to focus more with headphones, because it blocks background noises. Also, if it's a late night study session, you won't wake up anyone
• a tea or coffee. Coffee keeps you awake, green or black tea can make you feel more awake as well.
• Your study/work stuff: your laptop/tablet/phone , a few pens, paper or whatever you need.
•Anything else you could need, what about a heat pad, a blanket, a good lamp, your pet so you have a study buddy
Reminder:After an hour, you should stand up and walk a bit around. Better stop the music or put on different music for the break. Open your window, even if it's cold outside. Fresh air will make it better, trust me.
You could also lay your head down on your desk for ten minutes and listen to a podcast. Or, if you have to read a book, listen to the audiobook of it. You can also listen to the audiobook while doing another thing, that's even better than listening to music while reading the book.
I hope y'all had a good day, if not, that's okay too. Remember to take care of yourself and try to get some sleep tonight
who is even gonna read it
Koun padhega bro/sis.....😊
@ Pata nahi
Mein😅
@ Ha Ye Padhega
Kon kon up / bihar se hai
I LOVE YOU SIR ❤❤❤
AAP AA GAYE BAHUT KUSHI HO RAHI HAI❤❤❤❤
Itna late but exam ke 2 din pehle thanks sir 😊
Gajab bhai
Finally sound chapter
aagaya 💖🔥🔥
Kop🔥🔥🔥🔥
2:01:52 school wali madam 😁 is permanent
Pregnant 🌚🌚
@@pro_gamer_5 Dont defame Gamers
@unknown2009-0 don't defame unknown 🥶🥶
Kon kon paper me top karne ke lie dekh raha ha
vote for marathons for all subjects
Timestamps
00:04 - Introduction to key types of motion in physics.
00:47 - Lecture delayed but relevant for upcoming exams.
02:12 - Overview of Sound and Wave Motion in Class 9 Science.
03:00 - Understanding translational motion in physics.
04:14 - Understanding rotary and vibrational motion related to sound.
04:56 - Understanding the motion of particles in waves and vibrations.
07:15 - Understanding vibration through a spring-block system.
08:40 - वाइब्रेशन का साउंड में महत्व और मूल विचार
09:21 - Understanding sound requires knowledge of vibrations and waves.
10:58 - Wave motion causes particles to vibrate and transfer energy.
11:42 - Energy transfer involves vibrations and particle motion.
13:08 - Waves disturb particles in a medium during their motion.
13:54 - The difference between particle motion and wave motion is explained.
15:39 - Introduction to sound and wave motion concepts.
16:34 - Introduction to sound and wave types in Class 9 Science.
18:04 - Understanding longitudinal and transverse waves in particle motion.
18:56 - Slinky demonstrations reveal sound wave propagation concepts.
20:24 - Energy is transmitted through waves, disturbances in a medium.
21:45 - Longitudinal waves vibrate particles along the direction of wave motion.
23:33 - Water appears to move, but nothing is actually advancing.
24:20 - Understanding the effects of touching a leaf on water.
25:45 - Water does not flow without a potential difference.
26:31 - Sound waves exhibit oscillatory motion in different directions.
28:06 - Explains how particle movement affects each other when seated or standing.
28:45 - Experiment illustrating synchronization through standing and sitting movements.
30:16 - Understanding vibrations and transverse waves in sound.
31:31 - Understanding right angles and wave-particle vibrations.
33:13 - Understanding forces and waves without particles.
33:56 - Sound requires a medium to travel, unlike some waves.
36:11 - Sound is a mechanical wave requiring a medium for propagation.
37:07 - Sound waves require a medium; unlike electromagnetic waves, they don't.
38:34 - Introduction to sound and its production process.
39:21 - Sound is produced by vibrations from a source.
40:41 - वाइब्रेशन से साउंड उत्पन्न होता है और कणों का गतिशीलता का प्रदर्शन होता है।
41:36 - Sound is created by the movement of air particles.
43:01 - Sound is a longitudinal mechanical wave requiring particles for propagation.
43:57 - Sound requires medium and collision for production.
46:10 - Vibrations lead to sound wave propagation.
47:06 - Propagation of sound can be visualized using a guitar string analogy.
48:28 - Sound is created by the movement of particles and pressure variations.
49:13 - High and low-pressure regions create sound via compression and rarefaction.
51:41 - Understanding pressure variations through a distance-pressure graph.
52:42 - Understanding depression and troughs in longitudinal waves.
54:15 - Sound travels through longitudinal waves with specific particle movements.
55:08 - Sound requires a medium for propagation.
56:49 - Decreasing air pressure reduces sound intensity in bells.
57:35 - Sound requires a medium for propagation.
59:15 - Understanding wave properties and wavelength in sound.
1:00:01 - Wavelength is the distance between two adjacent crests or troughs.
1:01:42 - Understanding wavelength and frequency in sound.
1:02:31 - Understanding frequency in sound waves and its SI unit.
1:04:22 - Sound wave properties include frequency and tperiod
1:05:12 - Understanding period in wave motion.
1:07:01 - Frequency and period are inversely proportional.
1:07:47 - Understanding amplitude as displacement in vibrations.
1:09:26 - Understanding amplitude and sound wave characteristics.
1:10:27 - Waves are characterized by parameters affecting their distance traveled.
1:12:10 - Understanding wave velocity with its formula and components.
1:13:15 - Understanding the speed of sound in different mediums
1:15:02 - Sound travels at different speeds in solids, liquids, and gases.
1:15:51 - Speed of sound varies but is approximately 330-346 m/s.
1:17:25 - Pitch relates directly to frequency in sound.
1:18:35 - Sound properties depend on pitch and loudness factors.
1:19:58 - Timber refers to the quality of sound in different instruments.
1:20:42 - Different sounds arise from various materials, highlighting the concept of timbre.
1:22:01 - Sound intensity affects how we perceive loudness.
1:22:44 - Sound intensity can damage eardrums from loud sources.
1:24:23 - Reflection of sound depends on surface texture.
1:25:04 - Incident waves of sound interact with surfaces.
1:26:29 - साउंड रिफ्लेक्शन के लिए इन लॉज को समझना जरूरी है।
1:27:15 - Sound travels in a straight line and can be reflected properly.
1:28:36 - Echo occurs in closed spaces, unlike open areas.
1:29:24 - Echo occurs when sound reflects multiple times off surfaces.
1:30:57 - Sound persistence in a closed auditorium is due to repeated reflections.
1:31:42 - Understanding sound communication in everyday scenarios.
1:33:00 - Explains changes in audio quality over time in video production.
1:33:36 - Video quality and sound improvements over the years.
1:34:51 - Sound absorption properties of soft and hard materials.
1:35:33 - Methods to reduce reverberation in sound environments.
1:36:56 - Understanding the functioning of a stethoscope in sound detection.
1:37:37 - Understanding megaphone mechanics and sound direction.
1:39:06 - Sound energy is optimized through concave structures for effective reach.
1:40:02 - Surface shapes influence sound direction and clarity.
1:41:20 - Humans can hear frequencies between 20 Hz and 20,000 Hz.
1:42:15 - Sound is categorized into ultrasound and infrasound based on frequency ranges.
1:44:06 - Infrasound is not audible to humans but detected by animals.
1:44:59 - Human hearing range decreases with age and exposure.
1:46:37 - Ultrasound easily penetrates various materials due to its high frequency.
1:47:23 - Ultrasound applications include imaging for heart diagnostics.
1:48:38 - Ultrasonography uses sound waves to create images of internal organs.
1:49:20 - Ultrasound technology is crucial for monitoring and treating various health conditions.
1:50:36 - Ultrasound is effective for cleaning and detecting defects in electronic components and structures.
1:51:14 - Ultrasonic technology is used to detect underground leaks efficiently.
1:52:32 - Physics plays a critical role in detecting underwater threats.
1:53:17 - Ultrasound helps in navigation and hunting by echo location.
1:54:36 - Calculating wavelength using frequency and speed of sound.
1:55:33 - Sound waves take 3 seconds to travel and return.
1:57:19 - Understanding speed, distance, and time calculations.
1:58:04 - Understanding time and unit conversions in sound wave calculations.
1:59:48 - Sound travels at a speed of 700 meters per second.
2:01:05 - Importance of taking self-notes for effective learning.
2:02:36 - Encouragement for students to excel in Class 9 and transition to Class 10.
2:03:19 - Wrap-up of the class with farewell greetings.
1:35:22 Hesitation left the chat 💀🙏🏻
Yahi to chahiye tha SIR ❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤
1:53:18 dushman nai hamla kr lia
Jisne like nhi kiya toh wo exam mai fail
Bhai ab dil tut gya ab to fail hone ka man kar rha baar baar class me top kar ke thak gaya hu ab mujhe fail hona hai 😢😢😢
Bhai mere exam bhi khatm ho gaye aur Main pass bhi ho gaya to ab Main kaise exam mein fail ho sakta hun
Andi bandi sandi .... Agar tune ainda se aisi comment ki to
Aise comment likhane se pahle soch samajh Kar likha kar bhai
Tum fail ho jana okkkkk
1:35:40 😂😂😂 konsi genration
1:37:35 jaldi waha se hato ☠️
12:50 punishment dene ka tarik thoda casual hai
Thank you so much sir
Sab clear ho gya
Love from Neev 2025 ❤❤
Sir ek numericals ki class le lo plss 🙏
Tomorrow is my birthday 😄
13:27 ME KYA WAVE KA ENERGY TRANSFER SAME HOGA SABHI PARTICEL ME???😅
Who thinks that this worst chapter which confused us
1:30:16 form of hello
Sir ji maine notes aapke lecture ko dekhte dekhte hi bana liya h without pausing it so.. I'll practice with that❤😊❤
Mahaul pura wavy 〰️ 😂
Least chad teacher in pw 🗿🗿🗿
🎉 1:10:46 1:10:47
Thank you sir for this
video ❤
Sir finally ye chapter exam ke 3 days pehle aa hi gaya tha..
Don't take risk ,💀
Fail ho jayoge like kardo ☠️
For those who don't know porpoises are dolphins 1:43:44
Aap kya physics padhate ho ❤✅💯🔥🙏👌🫶🫶🫶🫶
Sir your mustache make you look like a angry teacher but you are not actually you are pretty humble 🙂
😅
16:36 really koi nahi bata ta 😢
First ❤❤
Please solve these two questions ❓...... ❤
Que:-. Write the coordinates of a point on x-axis at a distance of 4 units from origin in the
positive direction of x-axis and then justify your answer.
-------And-------
Que:-. Two coins are tossed simultaneously 500 times. If we get two heads 100 times,
one head 270 times and no head 130 times, then find the probability of getting one
or more than one head. Give reasons to your answer also.
Sir ji please live kariye marathon ki ❤❤❤❤❤❤❤ 0:20
53:30 *IMPORTANT* 🗿☠️
Vote for marathons ❤️👀😉
👇
Good Evening Sir, at 1:00:37 I informedyou correctly sir, please check the answer
permeability of a ferromagnetic material decreases as the magnetizing field increases
@rakshaksir
*Like for Ritik Sir*
Sir class9 marathon plzzz🥺🥺
12:21 gajabe bavkaal hai 😂
1:35:39 can do generation ✖✖✖✖✖
gendu generation✔✔✔✔✔
😂
Thanku sir 💜💜💜💜💜💜💜💜💜💜💜💜❤️❤️❤️❤️🧡🧡🧡🧡🧡🖤🖤🖤🖤🖤🖤🖤🤎🤎🤎🤎🤍🖤🧡🤍🧡🧡🧡🧡🧡🧡💚💚💚💚💙💙💙
Thankyouuu sooo muchh sir for uploading thiss!!!!!😭❤
😢 Sir 🥺 please 😢 important 😭 questions 😭 laaiye 😭 na 😭 please 🥺😭😭😭😭😭😭😭😭😭😭😭
Like nhi to fail every like = 90 precent
9th walo!!!!
9th ki physics badi pyaari hai jarur yaad karoge dekhna
Mein 10th mein hu isliye bol raha 🥀
Aisa kyu
@@DevanshPandey-mc9du kafi easy concept hote hai 9th mein.... favourite subject tha mera physics bilkul bhi hard nhi single formula se chapter khatam isliye....for me 9th class sabse easy class thi
Kitna wait krne ke baad 😢❤️❤️
physics with Raksak sir ❤❤😊😊
Thanks a lot sir......I'm waiting since from 2 month.....😅😅🎉🎉
1:23:14
Sir meri school wali madam nhi h Sir h 😅😅😅
53:48 sir ko gussaa aagya😂
Neevians attendence here 🎉
Present
thanks a lot❤❤❤❤❤❤❤
I am waiting for sound🔊
BEST TEACHER OF PHYSICS THANKYOU SO MUCH SIR
1:35:22 😂
Who is waiting this lecture for a long time???? ...😅😅😅....wo like kare...👍👍👍
*Jisne like nahi kiya woh 9th me fail*
*Don't take risk*
😂
👇
Eeet pathar 2025 only
I am watching from Pakistan ( hamsaya mulk
Jab sir mere friend ko marte hai to mujhe to bahut bahut maja aata hai 😅😅😂
Sir you're teaching style unmatched
concept pura feel hua❤❤❤
1:06:13 kya lyrics hai sir 💣
Who is backbenchers 😅😅 and who is topper 💫
(Comment in this emoji )
❤
😅😅
Thanku guruji main soch rahi thi kaha se padhu ❤❤
Sir class9 marathon plzzz
39:00 the chapter starts
Woo
Hm 1 week se paresan the is chapter ke liye .....😅
Hello Aarya ❤❤❤
Sir I was literally waiting for this vedio..and finally u uploaded this . thanks sir😊
Thank you sir ❤❤ pata nahi class kab chali recorded dekhungi thank you sir
Ye recorded hi hai
17th se exam start or 24ko exam khatam tk 1 week badh 1 march se br pushing chalu
region lga dunga is bar to
Wave sound
Good Evening Sir in the new recent video on the UA-cam Channel of NCERT WALLAH at 1:00:37 I was right about the answer of the question please check about it. Thank You
Good teacher of PW 😊😊❤❤❤ I like this video 😊😊❤❤❤❤❤❤❤🎉🎉🎉🎉🎉
Second ❤🎉🎉
Thanks sir for make this video, I was waiting to watch this chapter by you
finally sir sound chapter uploaded ❤❤💥
Very nice sir download kar ke dekho sab log ❤❤❤
Vote for all chapters revision
Kis kisko lagta hai ki school me rakshak sir ki tarah koi nahi padha sakta hai
❤❤❤❤❤
👇👍
most awaited vedio sir !
Thank you sir ❤❤
After a long time sound chapter
Sir ne samne mirror rakha hai 😂😂
Sir live marathon kb hogi i am a neevian❤❤
Hello
Sir hamare ghar main koi bhi tas nahi khelta 😂😂
Good afternoon noon sir
Yes sir
Love you sir and thanks
Finally mujhe laga aap bhol ge the....😢
30:04
Vote for Marathons
thanks sir
7th
❤😊