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प्रश्न
Boojho saw a cracker burst at night at a distance from his house. He heard the sound of the cracker a little later after seeing the cracker burst. Give reason for the delay in hearing the sound.
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उत्तर
The light travels faster than sound. So, the light from the cracker reaches faster than that of sound of the cracker.
Speed of light in air = 3 × 108 m/s
Speed of sound in air = 330 m/s
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संबंधित प्रश्न
Suggest measures to avoid noise pollution in classroom.
Explain in what way noise pollution is harmful to humans.
What is the safe limit of sound level in dB for our ears?
List two major harmful effects of the following:
Prolonged noise such as the one produced by crackers.
Look at a cartoonist's presentation of a kind of pollution given below.
 |
- Name the kind of pollution.
- List the sources of pollution.
- Mention any two harmful effects of this pollution.
Write the answer in your own words.
What measures will you take to control noise pollution?
Complete the table.
| Nature of sound | Unpleasant | Pleasant |
| Speaking | ||
| Whispering | ||
| Aeroplane sounds | ||
| Horns of Vehicles | ||
| Railway Engine | ||
| Rustling of leaves | ||
| Neighing of a horse | ||
| Ticking of a clock |
Mention a few measures to be taken to reduce the effect of noise pollution.
How does planting trees help in reducing noise pollution?
Unwanted disturbing sound, even if it is music next door, is noise.
