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TYPES OF WAVES
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Radio
waves
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| These are electromagnetic waves with large range of wavelength from a few mm to several meters. | |||
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Micro
waves
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| These are radio waves of wavelength between 1mm to 300mm. Microwaves are used in radar and microwave ovens. | |||
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Infra
red waves
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| These are thermal waves. They are emitted from hot bodies. Their wavelength is about 10-5 meter. | |||
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Visible waves
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| Visible waves have a wavelength range between 400nm to 700nm. The human eye is most sensitive to these waves. | |||
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Ultra violate waves
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| Waves having wavelength from 60nm to 380nm are known as ultra violet waves. Hot stars emit these waves. | |||
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Gamma
rays
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| Gamma rays have wavelength less than 1x10-11. Gamma rays are emitted by the nucleus of radioactive elements. They are also released during the nuclear reactions. | |||
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Green
house effect
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| For latest information , free computer courses and high impact notes visit : www.citycollegiate.com | |||
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Green
house
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| A chamber or house made to trap infra red radiation is called green house. Glass of green house allows the thermal radiation to pass through it and in this way the enclosed space is heated. Moreover glass is comparatively opaque to infra red radiation so, the heat is trapped in the green house, green house are used in the field of agriculture. A green house provides a stable and warm environment for plants for their proper growth. | |||
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Green
house effect
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| Gradual
rise in average global temperature due to absorption of infra red radiation
is called green house effect. Global rise in temperature is due to increase
in the amount of CO2 in the atmosphere. Some gases including CO2 allows
short wavelength of energy to pass towards the earth and heat it. However,
the hot earth emits only longer wavelengths (infra red) of energy back into space. These gases absorb infra red radiation before it escape. As result certain amount of heat retained in our atmosphere. This process which keep the earth warm is called green house effect. |
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Deadly
effects of
green house effect |
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| (1)
Rising sea level: due to increase in a temperature, ice will melt on
North & South poles resulting in a rise in sea level. (2) Climatic changes: droughts, floods, cyclones, hurricanes, fire in forest, temperature rise in summer & winter. (3) Ecological changes: rising oceans & climatic changes will change the natural environment and habitat of animals and plants. The effects of these are hard to predict but very serious. In the coming years the world will suffer a great deal due to increasing environmental pollution. |
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| For latest information , free computer courses and high impact notes visit : www.citycollegiate.com | |||