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Question
Assertion :Presently, the global atmosphere is warming up.
Reason :The depletion of stratospheric ozone layer has resulted in increase in ultraviolet radiations reaching the earth.
Assertion :Presently, the global atmosphere is warming up.
Reason :The depletion of stratospheric ozone layer has resulted in increase in ultraviolet radiations reaching the earth.
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Solution
The correct option is C If both the assertion and reason are true but the reason is not a correct explanation of the assertion
The warming up of global atmosphere present day is due to the increase in green house effect. Green house effect (GHE) describe the roles of water vapour, CO2 and other trace gases in keeping the Earth's surface warmer than it would be otherwise.These radiatively active gases are relatively transparent to incoming shortwave radiation (visible spectrum), but are relatively opaque to outgoing reradiating (infrared rays) longwave radiation. The latter radiation, which would otherwise escape to space, is trapped by these gases within the lower levels of the atmosphere.
The subsequent reradiation of some of the energy back to the surface maintains surface temperature higher than they would be if the gases were absent (without the green house effect the Earth's average global temperature would be 18 degree celsius rather than the present 15 degree celsius). There is concern that increasing concentration of the green house gases including CO2, CH4, and man made chlorofluorocarbons (CFCS),
may enhance the green house effect and cause global warming. Ozone layer present in the stratosphere is depleted by the aerosols and chloroflurocarbons. Ozone protects the earth from high energy ultra violet radiation.
So, the correct answer is 'If both the assertion and reason are true but the reason is not a correct explanation of the assertion'
The warming up of global atmosphere present day is due to the increase in green house effect. Green house effect (GHE) describe the roles of water vapour, CO2 and other trace gases in keeping the Earth's surface warmer than it would be otherwise.These radiatively active gases are relatively transparent to incoming shortwave radiation (visible spectrum), but are relatively opaque to outgoing reradiating (infrared rays) longwave radiation. The latter radiation, which would otherwise escape to space, is trapped by these gases within the lower levels of the atmosphere. The subsequent reradiation of some of the energy back to the surface maintains surface temperature higher than they would be if the gases were absent (without the green house effect the Earth's average global temperature would be 18 degree celsius rather than the present 15 degree celsius). There is concern that increasing concentration of the green house gases including CO2, CH4, and man made chlorofluorocarbons (CFCS), may enhance the green house effect and cause global warming. Ozone layer present in the stratosphere is depleted by the aerosols and chloroflurocarbons. Ozone protects the earth from high energy ultra violet radiation. So, the correct answer is 'If both the assertion and reason are true but the reason is not a correct explanation of the assertion'
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