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Basic Electricity Worksheet
38 questions By Tony R. Kuphaldt
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Question 19 of 38
What is the difference between DC and AC electricity? Identify some common sources of each type of electricity.
Reveal answerDC is an acronym meaning Direct Current: that is, electrical current that moves in one direction only. AC is an acronym meaning Alternating Current: that is, electrical current that periodically reverses direction (“alternates”).
Electrochemical batteries generate DC, as do solar cells. Microphones generate AC when sensing sound waves (vibrations of air molecules). There are many, many other sources of DC and AC electricity than what I have mentioned here!
Notes:Discuss a bit of the history of AC versus DC in early power systems. In the early days of electric power in the United States of America, there was a heated debate between the use of DC versus AC. Thomas Edison championed DC, while George Westinghouse and Nikola Tesla advocated AC.
It might be worthwhile to mention that almost all the electric power in the world is generated and distributed as AC (Alternating Current), and not as DC (in other words, Thomas Edison lost the AC/DC battle!). Depending on the level of the class you are teaching, this may or may not be a good time to explain why most power systems use AC. Either way, your students will probably ask why, so you should be prepared to address this question in some way (or have them report any findings of their own!).
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Question 20 of 38
Suppose you are building a cabin far away from electric power service, but you desire to have electricity available to energize light bulbs, a radio, a computer, and other useful devices. Determine at least three different ways you could generate electrical power to supply the electric power needs at this cabin.
Reveal answerThere are several different devices capable of producing electrical power for this cabin of yours:
- • Engine-driven generator
- • Solar cell
- • Thermopile
- • Windmill
For each of these devices, what is its operating principle, and where does it obtain its energy from?
Notes:For each of these electric power “sources,” there is a more fundamental source of energy. People often mistakenly think of generator devices as magic sources of energy, where they are really nothing more than energy converters: transforming energy from one form to another.
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Question 21 of 38
Where does the electricity come from that powers your home, or your school, or the streetlights along roads, or the many business establishments in your city? You will find that there are many different sources and types of sources of electrical power. In each case, try to determine where the ultimate source of that energy is.
For example, in a hydroelectric dam, the electricity is generated when falling water spins a turbine, which turns an electromechanical generator. But what continually drives the water to its “uphill” location so that the process is continuous? What is the ultimate source of energy that is being harnessed by the dam?
Reveal answerSome sources of electrical power:
- • Hydroelectric dams
- • Nuclear power plants
- • Coal and oil fired power plants
- • Natural gas fired power plants
- • Wood fired power plants
- • Geothermal power plants
- • Solar power plants
- • Tidal/wave power plants
- • Windmills
Notes:A great point of conversation here is that almost all “sources” of energy have a common origin. The different “sources” are merely variant expressions of the same true source (with exceptions, of course!).
Related Tools:
- Performance-Based Assessments for Semiconductor Circuit Competencies
- Specific Resistance of Conductors
