Choose the correct answer.
Sound can travel through
(a) gases only (b) solids only
(c) liquids only (d) solids, liquids and gases.
Answer :
(d) Sound can travel through solids, liquids, and gases.
Sound requires a medium to travel through. Solid, liquid and gas provide the medium for sound. Hence, sound can travel through solids, liquids and gases.
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Which of the following voices is likely to have minimum frequency?
(a) Baby girl (b) Baby boy
(c) A man (d) A woman
Answer :
(c) A man
The voice of an adult man is of lower pitch in comparison to the voices of a baby boy, a baby girl and a woman. Since frequency of a sound is directly proportional to its pitch, man's voice is of minimum frequency in comparison to a boy, a girl, or a woman's voice.
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In the following statements, tick 'T' against those which are true, and 'F' against those which are false.
(a) Sound cannot travel in vacuum. (T / F)
(b) The number of oscillations per second of a vibrating object is called its time period. (T / F)
(c) If the amplitude of vibration is large, sound is feeble. (T / F)
(d) For human ears, the audible range is 20 Hz to 20,000 Hz. (T / F)
(e) The lower the frequency of vibration, the higher is the pitch. (T / F)
(f) Unwanted or unpleasant sound is termed as music. (T / F)
(g) Noise pollution may cause partial hearing impairment. (T/F)
Answer :
Fill in the blanks with suitable words.
(a) Time taken by an object to complete one oscillation is called _________.
(b) Loudness is determined by the________ of vibration.
(c) The unit of frequency is _________.
(d) Unwanted sound is called _________.
(e) Shrillness of a sound is determined by the _________of vibration.
Answer :
A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency.
Answer :
The sound from a mosquito is produced when it vibrates its wings at an average rate of 500 vibrations per second. What is the time period of the vibration?
Answer :
Identify the part which vibrates to produce sound in the following instruments.
(a) Dholak (b) Sitar (c) Flute
Answer :
What is the difference between noise and music? Can music become noise sometimes?
Answer :
List sources of noise pollution in your surroundings.
Answer :
Explain in what way noise pollution is harmful to humans.
Answer :
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.
Answer :
Sketch larynx and explain its function in your own words.
Answer :
Lightning and thunder take place in the sky at the same time and at the same distance from us. Lightning is seen earlier and thunder is heard later. Can you explain?
Answer :
Science - NCERT Solution - Science : CBSE NCERT Exercise Solutions for Class 8th for Sound will be available online in PDF book form soon. The solutions are absolutely Free. Soon you will be able to download the solutions.
Science Class 10 Syllabus 2016-2017