Ncert – class 8- science – Chapter 10: Sound 1 Welcome to your Ncert - class 8- science - Chapter 10: Sound 1 1. An empty vessel produces louder sound than a filled one because. The air molecules in empty vessel have greater amplitude and hence greater intensity than liquid molecules in the filled vessel The density of air is less than the density of liquid contained in the vessel when filled The liquid in the filled vessel absorbs the vibrations of the liquid molecules The kinetic energy of particles constituting the air column is greater as compared to the kinetic energy of particles of liquid column None 2. Large amplitude of sound vibrations will produce: Meak sound Slow sound Shreak Loud sound None 3. Which of the following factor influence speed of sound most? Temperature Source of sound Nature of medium Humidity None 4. Low sound such as normal breathing has loudness up to 5 decibel 20 -30 decibel 50 - 60 decibel 10 decibel None 5. The voice box is called: Mouth Heart Stomach Larynx None 6. A metallic spoon falls on a metal plate making a huge sound and upon bouncing from the plate, it falls on to the pile of sand below it with no noise being heard. Sound is not heard on sand because Sound is absorbed by sand particles Vibration of metal plate is more than sand particles Sand does not vibrate Sound generated by the plate is more than the sand particles None 7. Statement 1: Loudness is the characteristic of a musical sound by which a loud sound can be distinguished from a faint sound.Statement 2: Echo is always produced when sound is incident on the hard and polished surface. Both statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1. Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1. Statement 1 is true but statement 2 is false Statement 1 is false but statement 2 is true None 8. .......... is the number of vibrations of a body in one second. Time-period Pitch Compression Frequency None 9. Vibrating part of flute is Rubber band Air-column String Stretched membrane None 10. When a tightly stretched band is plucked it Vibrate but do not produce sound Produce sound but do not vibrate Vibrate and produce sound Only oscillate to and fro None 11. In most of the cases vibration of objects are not visible because Amplitude is very small Wavelength is very small Wavelength is very large Frequency is very less None 12. Which of the following can caused by noise pollution? Hypertension All of the above Lack of sleep Anxiety None 13. In sound wave: Vibration of particles does not exist Direction of vibration of particle is same as direction of energy Direction of vibration of particle is perpendicular to the direction of energy None of these None 14. The hearing range of human ear is 20 Hz to 25,000 Hz Less than20 Hz 20 Hz to 20,000 Hz More than 20,000 Hz None 15. Which of the following require material medium for propagation? Sound All of these Light Transverse wave None 16. Eardrum is a part of Hearing organ Skeletal system Reproductive organ Sound producing organ None 17. Some whistles are designed to produce waves that can attract the attention of dogs but humans do not notice these waves. What kind of waves are these? These are supersonic sound waves. These are normal sounds waves whose frequency is more than 20,000 Hz. Humans cannot hear them because these waves have frequencies above the audible range These are electromagnetic waves. These are normal sounds waves whose frequency is less than 20 � 20 Hz. Humans cannot hear them because these waves have frequencies below the audible range. None 18. The siren of an ambulance needs to be a loud and piercing sound. Therefore, its main characteristics should be: high pitch and small amplitude high pitch and large amplitude low pitch and large amplitude low pitch and small amplitude None 19. The sound in the audible range is called Ultra sonic Sonic Sub sonic Light sound None 20. Which characteristic of the sound helps you to identify your friend by his voice while sitting with others in a dark room? The wavelength of the sound. The pitch of the sound. The speed of the sound. The frequency of the sound. None Time's up Please Share This Share this content Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Leave a Reply Cancel replyCommentEnter your name or username to commentEnter your email address to commentEnter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
