# AP Environmental Science : Solar Energy

## Example Questions

### Example Question #1 : Other Energy Sources

Charlie lives off-grid and gets his electricity from a 5,000 watt gasoline generator, but with the rising cost of fossil fuel, Charlie is looking to convert to solar energy. If a standard solar panel can generate 200 watts, how many panels would Charlie need to purchase if he wants to get the same energy output that he does with his gas generator?

Explanation:

Wattage is a measurement of electricity being generated over time. When compared to the 5,000 watt output of a conventional generator, a single solar panel generating watts cannot generate the same rate of electrical output. As a result, we will need multiple panels to generate an equal amount of electrical output. We can use dimensional analysis to determine how many panels we would need:

This calculation tells us that Charlie will need 25 standard solar panels to generate the same amount of electricity as one gasoline generator.

### Example Question #2 : Other Energy Sources

An important renewable energy source is solar power. Solar power works by storing sunlight in batteries using which type of cells?

Thermal cells

Photovoltaic cells

Eukaryotic cells