Ncert – class 8- science – Chapter 10: Sound 1 Welcome to your Ncert - class 8- science - Chapter 10: Sound 1 1. The voice box is called: Mouth Stomach Heart Larynx None 2. The sound in the audible range is called Ultra sonic Sonic Light sound Sub sonic None 3. 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 Vibration of metal plate is more than sand particles Sand does not vibrate Sound generated by the plate is more than the sand particles Sound is absorbed by sand particles None 4. 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 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 supersonic sound 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. These are electromagnetic waves. None 5. .......... is the number of vibrations of a body in one second. Time-period Compression Pitch Frequency None 6. 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. Statement 1 is true but statement 2 is false Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1. Statement 1 is false but statement 2 is true None 7. When a tightly stretched band is plucked it Vibrate and produce sound Vibrate but do not produce sound Only oscillate to and fro Produce sound but do not vibrate None 8. In most of the cases vibration of objects are not visible because Amplitude is very small Frequency is very less Wavelength is very large Wavelength is very small None 9. Which of the following require material medium for propagation? All of these Sound Transverse wave Light None 10. Eardrum is a part of Sound producing organ Hearing organ Skeletal system Reproductive organ None 11. In sound wave: Vibration of particles does not exist None of these Direction of vibration of particle is perpendicular to the direction of energy Direction of vibration of particle is same as direction of energy None 12. Which of the following factor influence speed of sound most? Humidity Temperature Source of sound Nature of medium None 13. Large amplitude of sound vibrations will produce: Shreak Meak sound Slow sound Loud sound None 14. Which of the following can caused by noise pollution? Hypertension Anxiety Lack of sleep All of the above None 15. The siren of an ambulance needs to be a loud and piercing sound. Therefore, its main characteristics should be: low pitch and large amplitude high pitch and small amplitude high pitch and large amplitude low pitch and small amplitude None 16. Vibrating part of flute is String Stretched membrane Rubber band Air-column None 17. Low sound such as normal breathing has loudness up to 10 decibel 20 -30 decibel 5 decibel 50 - 60 decibel None 18. 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 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 The density of air is less than the density of liquid contained in the vessel when filled None 19. The hearing range of human ear is More than 20,000 Hz 20 Hz to 20,000 Hz Less than20 Hz 20 Hz to 25,000 Hz 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 pitch of the sound. The speed of the sound. The wavelength 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.
