Same chapter3 marksDifficulty: Medium
What is thermal expansion? Give one everyday example of it being allowed for.
Heat and Energy
3 marksDifficulty: Medium
What is the greenhouse effect and why is it a matter of concern?
Original Khojo Papers practice question — not from a past board paper.
Answer
Certain gases in the atmosphere, chiefly carbon dioxide, methane and water vapour, let the sun's short-wave radiation through but absorb the long-wave infrared radiation the earth re-emits, so heat is trapped and the surface stays warm. It is a concern because the burning of fossil fuels has raised the concentration of these gases and is warming the planet, raising sea levels and disturbing the climate.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Without any greenhouse effect the earth would be far too cold for life; the problem is its enhancement.
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