Class 9 Physics Chapter 11 Sound MCQ with Answers – Complete Quiz Bank
Sound is one of the most fascinating chapters in Class 9 Physics, covering everything from vibrations and frequency to the Doppler effect and noise pollution. Our comprehensive MCQ quiz bank helps you master all concepts from NCERT Chapter 11 with confidence. Whether you're preparing for school exams or competitive entrance tests, these carefully curated multiple-choice questions align perfectly with the CBSE curriculum. Practice with real questions, understand the reasoning behind each answer, and build strong foundational physics knowledge with CBSETUTOR.ai — India's most trusted AI tutor for CBSE students.
Your child's private AI tutor — trained on NCERT.
3-day free trial · ₹1 to start · Cancel anytime.
Understanding Sound Waves and Vibrations in NCERT Chapter 11
Sound is produced by vibrations and travels in the form of mechanical waves through a medium. According to NCERT Class 9 Physics Chapter 11, sound requires a material medium (solid, liquid, or gas) to propagate. Unlike light, sound cannot travel in a vacuum. The chapter emphasizes that sound waves are longitudinal waves where particles oscillate parallel to the direction of wave propagation. Our MCQ questions test your understanding of wavelength, frequency, amplitude, and the relationship between these properties.
Frequency, Pitch, and Loudness – Key MCQ Topics
Frequency refers to the number of vibrations per second, measured in Hertz (Hz). Pitch is the characteristic of sound that determines how high or low it seems, directly related to frequency. Loudness depends on amplitude and is measured in decibels (dB). NCERT Chapter 11 explains that humans can hear frequencies ranging from 20 Hz to 20,000 Hz. Our quiz bank includes multiple-choice questions that help distinguish between these concepts, a common source of confusion among Class 9 students.
Speed of Sound in Different Media
The speed of sound varies depending on the medium through which it travels. In air at 25°C, sound travels at approximately 343 m/s. NCERT Chapter 11 notes that sound travels faster in liquids and solids than in gases. For example, sound travels at about 1,480 m/s in water and roughly 5,000 m/s in steel. Understanding these differences is crucial for solving numerical problems. Our MCQ questions include scenarios where students must recall and apply these values correctly.
Echo, Reverberation, and Reflection of Sound
An echo occurs when sound reflects off a surface and reaches the listener after a time delay—typically requiring a distance of at least 17 meters for humans to distinguish it as separate from the original sound. Reverberation happens when reflected sound arrives so quickly that it blends with the original sound. NCERT Chapter 11 explains these phenomena and their practical applications in concert halls and auditoriums. Our quiz includes questions on calculating echo distances and understanding acoustic design principles.
The Doppler Effect – Essential MCQ Questions
The Doppler effect describes the change in frequency of sound when the source or observer moves relative to each other. When a source moves toward an observer, the frequency increases (pitch becomes higher). When it moves away, frequency decreases (pitch becomes lower). NCERT Chapter 11 provides real-world examples like ambulance sirens and train whistles. Our MCQ bank includes questions testing your ability to predict frequency changes and understand the physics behind everyday observations.
CBSETUTOR.ai: India's Most Trusted AI Tutor for CBSE Physics
Over 50 lakh CBSE families across India trust CBSETUTOR.ai for mastering chapters like Sound with interactive quizzes, instant doubt resolution, and personalized learning paths. Our AI tutor provides 24/7 support in Hindi and English, making complex physics concepts accessible to every student. With our adaptive learning technology, you get real-time feedback on MCQ performance, detailed explanations for wrong answers, and customized practice sessions. Thousands of Class 9 students have improved their physics scores using CBSETUTOR.ai's comprehensive quiz banks and expert pedagogy.
Noise Pollution and Human Hearing – Chapter Context
NCERT Chapter 11 addresses the growing problem of noise pollution in urban areas. Sound levels above 80 dB can cause hearing damage with prolonged exposure. The chapter categorizes sounds by their intensity levels: normal conversation (60 dB), heavy traffic (80 dB), and jet aircraft (140 dB). Understanding these levels helps students appreciate the importance of noise control measures. Our MCQ questions connect theoretical physics knowledge to environmental science, helping students see real-world applications.
Numerical Problems: Speed, Distance, and Time Calculations
Class 9 Physics Chapter 11 includes numerical problems involving the formula: Speed = Distance / Time. Students must calculate echo distances, determine time intervals for sound travel, and solve problems involving multiple reflections. NCERT examples use scenarios like thunder and lightning to test application skills. Our MCQ quiz bank includes numeric answer options that require careful calculation, not just conceptual understanding. These questions prepare you for both school exams and entrance assessments.
Infrasound, Ultrasound, and Frequency Ranges
Sounds with frequencies below 20 Hz are called infrasound, and those above 20,000 Hz are ultrasound. Both are inaudible to humans but have important applications. NCERT Chapter 11 explains that animals like dogs, bats, and dolphins use ultrasound for communication and navigation. Medical ultrasound uses frequencies around 2-10 MHz for imaging. Our MCQ questions test your knowledge of frequency ranges, applications of ultrasound in medicine and industry, and animal communication.
Preparing for CBSE Exams with Sound Chapter MCQs
The Sound chapter typically comprises 10-15% of Class 9 Physics board exams, with questions appearing in both MCQ and short-answer formats. Key topics include wave properties, speed of sound, echo, Doppler effect, and noise pollution. CBSETUTOR.ai's structured MCQ approach helps you cover all learning objectives from the NCERT syllabus systematically. By practicing diverse question types with instant feedback, you build confidence for written exams and develop problem-solving speed essential for competitive entrance tests.
Frequently asked questions
What is the minimum distance required to hear a clear echo according to NCERT Chapter 11?+
According to NCERT, a minimum distance of about 17 meters is required for the human ear to distinguish a clear echo from the original sound. This distance allows sufficient time delay between the original and reflected sound waves.
How fast does sound travel in water compared to air?+
Sound travels at approximately 343 m/s in air at 25°C, but about 1,480 m/s in water—roughly 4.3 times faster. This demonstrates that sound travels faster in denser media, an important concept covered in NCERT Chapter 11.
Does CBSETUTOR.ai offer free trial access to the Sound chapter MCQ quiz?+
Yes, CBSETUTOR.ai provides free trial access to selected chapters including Sound. You can explore the quiz bank, attempt sample questions, and experience the AI-guided learning platform before subscribing to full features.
Is CBSETUTOR.ai available in Hindi medium for Class 9 Physics?+
Absolutely. CBSETUTOR.ai fully supports Hindi-medium students with complete Chapter 11 content, MCQs, explanations, and doubt resolution in Hindi. Our 24/7 AI tutor helps both English and Hindi-medium CBSE students equally.
What does the Doppler effect mean in simple terms?+
The Doppler effect is the change in sound frequency when the source or listener moves. An approaching ambulance has higher pitch; a departing one has lower pitch. NCERT Chapter 11 explains this with everyday examples students can relate to.
What is the difference between pitch and loudness in sound?+
Pitch depends on frequency (how high or low sound seems), while loudness depends on amplitude and measured in decibels. High-frequency sounds have high pitch; large-amplitude sounds have high loudness. NCERT Chapter 11 clearly distinguishes between these two properties.
Can sound travel through vacuum according to NCERT Chapter 11?+
No. Sound is a mechanical wave requiring a medium (solid, liquid, or gas) to propagate. It cannot travel through vacuum, which is a fundamental concept emphasized in NCERT Class 9 Physics Chapter 11.
How many chapters are covered in CBSETUTOR.ai's Physics MCQ library for Class 9?+
CBSETUTOR.ai covers all 15 chapters of CBSE Class 9 Physics with comprehensive MCQ banks, detailed explanations, and adaptive learning paths. Each chapter includes 50+ carefully curated questions aligned with NCERT 2024-25 curriculum.
Related resources
Class 9 Physics Chapter 7: Motion – Complete Notes, Definitions & ExamplesNCERT Solutions for Class 9 Physics Chapter 9: Gravitation (Complete Guide)Online Class 9 Physics Tutor in Mumbai — 24/7 AI Coaching at ₹9,999/MonthNCERT Solutions for Class 9 Physics Chapter 7: Motion – Complete Solved GuideNCERT Solutions for Class 9 Physics Chapter 8: Force and Laws of MotionClass 9 Physics Chapter 8: Force and Laws of Motion – Complete Notes & Revision GuideOnline Class 9 Physics Tutor in Delhi — 24/7 AI Coaching for CBSE Board SuccessClass 9 Mathematics Chapter 1: Orienting Yourself – The Use of Coordinates MCQ Quiz with Answers
Keep learning — related guides
Sanskrit
Class 9 Sanskrit Chapter 12 वाङ्गमयं तपः: 30 MCQ Questions with Answers & Explanations
Sanskrit
Class 9 Sanskrit Chapter 11 पर्यावरणम् MCQ Quiz – 30 Questions with Answers
Sanskrit
Class 9 Sanskrit Chapter 10 जटायोः शौर्यम् MCQ Quiz – 30 Questions with Answers & Explanations
Sanskrit
Class 9 Sanskrit Chapter 9 सिकतासेतुः MCQ Quiz with Answers (2024–25 CBSE Syllabus)
Sanskrit
Class 9 Sanskrit Chapter 8 लौहतुला: 30 MCQs with Answers & Explanations
Sanskrit
Class 9 Sanskrit Chapter 7 प्रत्यभिज्ञानम् MCQ Quiz – 30 Questions with Answers
Ready to give your Class 9 child the tutor that never sleeps?
CBSETUTOR.ai covers every chapter in the Class 9 NCERT syllabus — Maths, Science, Social Science, English, Hindi and more. 24×7. Patient. Unlimited. 3-day free trial.
Start your child's 3-day free trial →