Sound class 9

You will find NCERT Solutions for Class 9 Science Chapter 12 Sound that help you in improving the marks in the examinations and have edge over your classmates. These Class 9 NCERT Solutions are curated by the experts in a comprehensive which can be helpful in clearing your doubts instantly. It will serve as beneficial tool that can be used to recall various questions any time. Through these NCERT Solutions, students should not waste time and allow students to cover the entire syllabus effectively without any frustration. Chapter 12 Sound NCERT Questions and Answers will give good experience and provide opportunities to learn new things. It help the students in learning complex topics and problems in an easy way. Your marks play an important role in shaping future thus these Class 9 Science NCERT Solutions will become your comprehensive guide in easy learning and evaluating yourself. It will make you understand the topics in most simple manner and grasp it easily to perform better. Students should also refer previous year questions and practise test papers and worksheets to assess their key areas. When an object vibrates,it sets the particles of the medium around it vibrating.The particles in the medium in contact with the vibrating object displace from its equilibrium position. It then exerts force on the adjacent particles. After displacing the adjacent particle the first particle of medium comes back in its original position. This process continues in the medium till the...

According to the CBSE Syllabus 2023-24, this chapter has been renumbered as Chapter 11. Particles in Waves Introduction to Waves A wave is a disturbance in a medium which movesfrom one point to another and carries energy without a net movement of particles. It may take the form of elastic deformation or a variation of pressure. E.g. A rubber cork on the water that goes up and down when a rock falls into the water creates a ripple. For more information on Particulars in Waves, watch the below video To know more about Wave Particles Dual Nature, Particle Motion of Mechanical Waves (i) Transverse Waves Particle motion is perpendicular to the direction of wave motion. This type of wave is a mechanical wave. E.g.Light and Mexican wave in a stadium. (ii) Longitudinal waves Particles travel parallel to the direction of wave motion by means of successive compressions or elongations. This is also a mechanical wave. E.g. Sound waves in the air. For more information on Types of Sound Waves, watch the below video To know more about the Types of Waves, Sound Properties Introduction to Sound Waves Sound needs a medium to propagate. The matter or material through which soundpropagates is called a medium. When particles vibrate about their mean positions, it pushes a region of compressed air, creating a region of high pressure, followed by a region of low pressure as the particle retreats to its mean position. The soundwave propagatesbycompressions and rarefactionsofparticles in amedium. ...

Theory • Sound: It is a form of energy produced by vibration and it needs medium to propagate. • Reflection of sound: As light reflects when it strikes any hard object (opaque), sound also gets reflected when it strikes any object. Laws of Reflection of sound • The angle of incidence is always equal to the angle of reflection. • The incident sound wave, the normal and the reflected sound wave lie in the same plane. Materials Required Two highly polished metal tubes made up of stainless steel or aluminium of length 25 cm and diameter 2 cm, a drawing sheet, metal plate, a geometrical set, thumb pins, drawing board/table, stopwatch, metal stand. Procedure • Fix the white sheet on drawing board with thumb pin. • Draw a line AB to place the metal plate as reflecting surface with the help of metal stand, and draw normal OP to this line as shown in the figure. • Now draw a line OC making an angle of 30° with the line OP. • Place one metal tube near to the point O of normal and metal plate on the line OC. • Place the ticking watch closer to one end of this metal tube. • Now place the second tube so that its one end is near to the point O. Bring your ear close to the other end and adjust its position such that it colle cts the maximum reflected sound. • Mark the position of the tube when it collects the clear and maximum reflected sound. • Draw an extended line of reflected sound wave and mark it as OD. • Measure the angle of incidence and the angle of reflection. • Follow the abov...

Sound Class 9 Extra Questions Science Chapter 12 Extra Questions for Class 9 Science Chapter 12 Sound Sound Class 9 Extra Questions Very Short Answer Questions Question 1. What does wave transfer—matter or energy? Answer: Energy. Question 2. What are mechanical waves? Answer: Waves that are characterised by the motion of particles in a medium are called mechanical waves. Mechanical waves require material medium for their propagation. Question 3. Where is the density of air higher—at compressions or at rarefactions? Answer: At compressions. Question 4. What is one complete oscillation? Answer: The change in density from one maximum value to the minimum value and again to the maximum value makes one complete oscillation. Question 5. On what factor does the pitch of a sound depend? Answer: The pitch of a sound depends on the frequency of vibrations. Actually, the pitch of a sound is directly proportional to its frequency. Question 6. What is the wavelength in the given curve? Answer: AE Question 7. If any explosion takes place at the bottom of a lake, what type of shock waves in water will take place? [NCERT Exemplar] Answer: Longitudinal waves. Question 8. What is intensity of sound? Answer: The amount of sound energy passing through unit area each second is called the intensity of sound. Question 9. What is relation between time period and frequency? Answer: Frequency = \(\frac\) = 3 × 10 3 m = 3 km. Filed Under:

Class 9 Science Chapter 12 Extra Questions and Answers Sound Extra Questions for Class 9 Science Chapter 12 Sound with Answers Solutions Sound Class 9 Extra Questions Very Short Answer Type Question 1. What are longitudinal waves? Answer: A wave in which the particles of the medium vibrate back and forth in the ‘same direction’ in which the wave is moving, is called as a longitudinal wave. Question 2. What are transverse waves? Answer: A wave in which the particles of the medium, vibrate up and down ‘at right angle’ to the direction in which the wave is moving, is called a transverse wave. Question 3. Define wavelength. What is its symbol and its SI unit? Answer: The distance between two consecutive compressions (C) or two consecutive rarefactions (R) is called the wavelength. The wavelength is denoted by (Greek letter ‘lambda’). Its SI unit is the metre (m). Question 4. Define frequency. What is its symbol and its SI unit? Answer: The number of complete waves (or cycles) produced per second is called a frequency of sound waves. It is denoted by f. The SI unit of frequency is hertz (Hz). Question 5. What is one hertz? Answer: A vibrating body producing 1 wave per second is said to have a frequency of 1 Hz. Question 6. Define amplitude. What is its symbol and its SI unit? Answer: The magnitude of the maximum disturbance in the medium on either side of the mean value is called the amplitude of wave. It is denoted by A. The SI unit is the metre (m). Question 7. What is ‘audib...