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