Ncert – class 8- science – Chapter 10: Sound 1 Welcome to your Ncert - class 8- science - Chapter 10: Sound 1 1. Eardrum is a part of Skeletal system Hearing organ Reproductive organ Sound producing organ None 2. .......... is the number of vibrations of a body in one second. Pitch Time-period Frequency Compression 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 Sand does not vibrate Sound is absorbed by sand particles Vibration of metal plate is more than sand particles Sound generated by the plate is more than the sand particles None 4. Which of the following can caused by noise pollution? All of the above Lack of sleep Anxiety Hypertension None 5. 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 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. None 6. Large amplitude of sound vibrations will produce: Slow sound Meak sound Shreak Loud sound None 7. 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 small amplitude low pitch and large amplitude None 8. Vibrating part of flute is Air-column String Stretched membrane Rubber band None 9. 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 true but statement 2 is false 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 10. 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 11. Low sound such as normal breathing has loudness up to 5 decibel 10 decibel 50 - 60 decibel 20 -30 decibel 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. 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 14. The voice box is called: Stomach Larynx Heart Mouth None 15. Which of the following require material medium for propagation? Light Transverse wave All of these Sound None 16. 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 17. 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 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 The liquid in the filled vessel absorbs the vibrations of the liquid molecules None 18. Which of the following factor influence speed of sound most? Source of sound Temperature Humidity Nature of medium None 19. 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 wavelength of the sound. The speed of the sound. The pitch of the sound. None 20. The sound in the audible range is called Sonic Light sound Ultra sonic Sub sonic 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.
