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