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