8th Class Science Sample Paper Science Sample Paper-2

  • question_answer                       
    (i) What are audible and inaudible sounds? Write the range of audible frequency for human ear.
    (ii) Explain in what way noise pollution is harmful for humans.                             



    (i) Audible sound: 20 Hz to 20,000 Hz is audible for human beings.                                  
    This is also called as Sonic Sound.                                                                                               
    Inaudible sound:
    (a) Sound less than 20 Hz frequency is called infrasonic sound.
    (b) Sound more than 20,000 Hz frequency is called ultrasonic sound.
    These both are inaudible to human ears.                                                                                       
    (ii) Lack of sleep, hypertension (high blood pressure), anxiety and many more health disorder may be caused by noise pollution. Noise pollution also causes the temporary or even permanent deafness in human being.


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