Review of Chapter 9 (and 8)

Wavespeed = (wavelength) X (frequency)
Speed of light waves = 3 X $10^8$ m/sec
Speed of sound waves = 340 m/sec

1. Can light travel through a vacuum?

(yes or no) Cite evidence or a situation which supports your answer.

2. Black body radiation

This graph shows the relative amount of energy in the spectrum of our sun, a lightbulb, and an unknown star (?). Is the unknown star hotter or colder than our sun??

3. Earth’s ozone layer

protects us by absorbing sunlight in what part of the electromagnetic spectrum?

What are two hazards of this kind of light?

The ultra-violet part. Ozone is "O₃".

• sunburn
• skin cancer
• cataracts
• phytoplankton (bottom of Antarctic food web) are vulnerable
• genetic damage to plants & animals

4. CFCs are chemicals

which have been used for

1. refrigeration
2. air conditioning
3. released as a result of deforestation
4. fuel for submarines
5. a propellant in spray cans
6. a gas all mammals expel as a normal byproduct of digestion

5. A radio wave

is emitted in New York, and received in Phoenix—about 3400 km away. How long does it take for the radio wave to travel from New York to Phoenix?

Closest to… a. 0.01 seconds b. 1 second c. 10 seconds d. 10,000 seconds

6. Which of these makes the ozone problem worse?

1. gasoline engines
2. CFC coolants
3. nuclear power plants
4. hydroelectric power plants
5. solar heating of homes

7. What energy transformation occurs

(from what type to what type) in each of these cases? (Each one involves *radiant energy* as either the starting or ending type.)

...solar radiation warms your skin.

...in a flashlight.

...a microwave oven warms your food.