Question

Assertion: (A) A gradual increase in the overall levels of temperature of the earth’s atmosphere is called as global warming. Reason:(R) The global warming has no effect on the ecosystem. a: Both assertion (A) and reasoning(R) are true and reasoning is the correct explanation of assertion. b: Both assertion (A) and reasoning(R) are true but the reasoning is not the correct explanation of assertion. c: Assertion (A) is true but reasoning (R) is False. d: Assertion (A) is False but reasoning (R) is true.​

Answer 1

c

Assertion (A) is true but reasoning (R) is False.

Answer 2

Answer:

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Class 12

>>Biology

>>Environmental Issues

>>Greenhouse Effect and Global Warming

>>Assertion :Presently, the global atmosph

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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.

Medium

AIIMS

Solution

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Correct option is B)

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, CO

2

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 eff