The Greenhouse Effect

Conceptual Physics

Text Correlation: Section 22.7

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Question 1

• To keep the interior of a car from heating too much, it is common to put a reflecting surface behind the windshield. How does this work?

• Answer: Light does not change frequency when reflected (a blue shirt is still blue in a mirror!) .So light that has a frequency to get through glass in the first place will reflect back through the glass.

• Light that gets absorbed, however, is not reradiated at the same frequency. The reemitted light has a frequency proportional to the temperature of the emitter. The low frequency of this reradiated light keeps it from getting through the glass.

Question 2

• Is the greenhouse effect something the world would be better without?

• Answer: No! Without the greenhouse effect, the world's average temperature would be a frigid -18°C. The environmental concern is too much greenhouse effect.