Science - Grade 8 (C ...

Q52. What is the frequency of a vibrating body whose time-period is 0.05 second?

 

Q53. By how much will the loudness of a sound change when the amplitude of vibrations is: (a) doubled? (b) halved?

 

Q54. Your parents are going to buy a house. They have been offered one on the roadside and another three lanes away from the roadside. Which house would you suggest your parents should buy? Explain your answer.

 

Q55. Explain in what way noise pollution is harmful to humans.

 

Q56. What is the frequency of the sound produced when the vocal cords are: (a) tight and thin? (b) loose and thick?

 

Q57. Write the loudness of the following in decibels:

Normal breathing, Soft whisper (at 5m), Normal conversation, Busy traffic and Average factory

 

Q58. How do we hear?

 

Q59. Identify the part which vibrates to produce sound in the following instruments: (a) Dholak (b) Sitar (c) Flute (d) Cymbals (e) Veena (f) Tabla

 

Q60. List sources of noise pollution in your surroundings.

 

Q61. What is the difference between noise and music? Can music become noise sometimes?

 

Q62. Sketch larynx and explain its function in your own words.

Or

Describe how sound is produced by the human voice box (or larynx).

 

Q63. State the various measures which can be taken to control noise pollution in our surroundings.

 

Q64. How can you show that sound cannot travel through a vacuum?