S13. Sound | General Science | Class 6

1. Fill in the blanks with the proper words.

(a) The propagation of sound does not occur through a ……….. .

ANSWER: vacuum

(b) Noise pollution is a ………. issue.

ANSWER: serious/ social

(c) The sound which is disagreeable to the ears is called….. .

ANSWER: noise

(d) Noise has adverse effects on our ………. .

ANSWER: health

2. What should we do ?

(a) The silencer of a motorcycle is broken.

ANSWER: We should get it repaired from a mechanic.

(b) A factory in the surroundings is producing continuous loud noise.

ANSWER: The factories should be situated away from residential areas or we can contact the Authorities to control the noise pollution.

3. Write the answers in your own words.

(a) What is meant by vibration?

ANSWER: The to and fro motion of an object about its mean position is called its vibration.

(b) Explain with the help of practical examples how sound is propagated through solids.

ANSWER: Sound propagates through solids in form of waves. The examples are:

(i) When we place our ears at one end of the bench and tap at the other end we can hear the tapping more loud and clearly.

(ii) When we use a string telephone, we can hear the words clearly as the sound travels through the thread, which is a solid.

(c) What is meant by noise pollution?

ANSWER: A loud sound is harsh to the ear and such sounds produce noise. Noise pollution occurs due to occurs when we continuously hear one or many sounds harmful to the ear. Noise pollution has adverse effects on our health.

(d) What measures will you take to control noise pollution ?

ANSWER: Measures for preventing noise pollution

• As far as possible, we should avoid blowing the horn.
• The volume of the TV or radio in the house should not be too loud.
• Vehicles should be maintained properly to reduce the unnecessary sounds they produce.
• Factories, airports, railway stations and bus stands should be located, away from residential areas.

4. Complete the table.

Nature of sound	Unpleasant	Pleasant
a. Speaking
b. Whispering
c. Aeroplane sounds
d. Horns of Vehicles
e. Railway Engine
f. Rustling of leaves
g. Neighing of a horse
h. Ticking of a clock

ANSWER:

Nature of sound	Unpleasant	Pleasant
a. Speaking		Yes
b. Whispering		Yes
c. Aeroplane sounds	Yes
d. Horns of Vehicles	Yes
e. Railway Engine	Yes
f. Rustling of leaves		Yes
g. Neighing of a horse	Yes
h. Ticking of a clock		Yes

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