Quiz: What You Don't Know About Electricity


Photograph by Photopix

You know how much you rely on those wall outlets to stay cool, power your toys, and keep your food fresh. But how much do you really know about how electricity gets to your home?

Which of these scientific pioneers is credited with establishing the first commercial electric power plant?

  • Benjamin Franklin
  • Michael Faraday
  • Thomas Edison
  • Nikola Tesla

Thomas Edison’s Pearl Street Station electrified a one-square-mile (2.6-square-kilometer) area of Lower Manhattan beginning September 4, 1882, providing power to illuminate his new electric light bulbs. The world’s first commercial electric power plant operated until it was destroyed by fire in 1890.

This quiz has been amended from a previous version to specify that Edison's was the first commercial plant. Sigmund Schuckert is credited with building the world's first power station in Bavaria in 1878.

Why was an elephant electrocuted in New York in the early days of electric service?

  • By accident, when Edison’s power plant at Luna Park Zoo at Coney Island malfunctioned.
  • On purpose, in an effort by Edison to demonstrate the danger of high-voltage electricity.
  • In an experiment by Edison to test the principles of direct-current transmission.
  • Edison defended himself against a rampage while stringing transmission wire at Luna Park Zoo.

Edison staged the electrocution of a Luna Park Zoo elephant (one already slated for euthanasia), to show the dangers of competitor Westinghouse’s alternating current (AC) system. In the end, though, the long-distance-transmission advantages of AC won out over Edison’s direct current.

Why isn’t electricity considered a primary energy source?

  • It is not as powerful as other energy sources.
  • It is not the most common energy source.
  • It was not the first energy source discovered.
  • It is produced by another energy source.

Electricity is considered a secondary energy source because it is produced by the conversion of another energy source, such as coal, natural gas, nuclear power, wind, or solar energy.

Coal, hydroelectric, wind, nuclear, and solar thermal power plants all have this equipment in common.

  • Photovoltaic cells
  • Boilers
  • Turbines
  • Flues

In all of these plants, steam, wind, or water is used to turn turbines. The turbine is connected to a generator—a long, coiled wire surrounded by a magnet. The conducting wire’s movement through the magnetic field causes electric current to flow through the wire. That current is sent to the grid.

How does flipping a switch turn a light on?

  • It steps up the voltage.
  • It generates an electromagnetic field.
  • It opens the circuit.
  • It closes the circuit.

Flipping a light switch on closes, or completes, the electrical circuit. This closed loop or complete path allows electricity to flow through the light bulb.

What units do electric companies generally use to measure how much power you use?

  • Amperes
  • Kilowatt-hours
  • Kilowatts
  • Volts

Electricity use is generally measured in kilowatt-hours, the amount of energy used over time—that’s how the electric company figures your monthly bill. An ampere is a measure of electric charge, and a volt is a measure of electric potential difference.

How long would you have to keep a ten-watt compact fluorescent lightbulb turned on to consume one kilowatt-hour of electricity?

  • 1 hour
  • 10 hours
  • 100 hours
  • 1,000 hours

A ten-watt CFL bulb turned on for 100 hours would consume 1,000 watt-hours, or one kilowatt-hour of electricity. A 100-watt incandescent bulb would consume the same amount of electricity in just ten hours.

What devices on the electric grid allow the high-voltage electricity that travels long distances on power lines to be transmitted to homes and businesses at the lower voltages needed for appliances?

  • Transformers
  • Circuits
  • Turbogenerators
  • Synchrophasors

Power plants produce electricity at high voltage so it can be moved over long distances efficiently, with minimal transmission losses. Transformers are needed throughout the system to step down the voltage so it can be used in households and businesses.

Which of the following can cause disruptions to electricity service?

  • Sea salt
  • Squirrels
  • Sunspots
  • All of the above

Power failures can be caused by coastal sea salt deposits on power line insulators, by animals contacting wires, and by coronal mass ejections from solar storms that originate in sunspots. Most power companies report that weather is the leading source of outages.

Which of the following major power blackouts left the most people in the dark?

  • Brazil, November 2009
  • United States and Canada, August 2003
  • China, January and February 2008
  • Western Europe, November 2006

Lightning storms triggered a major failure at Itaipu Dam and its grid, disrupting electricity for 87 million people in Brazil and Paraguay for about seven hours. The North American outage affected 50 million people, China’s affected 30 million, and Europe’s affected 10 million.

In 2012, the world’s longest electric transmission line was under construction in what country?

  • China
  • Denmark
  • Brazil
  • South Africa

The Rio-Madeira HVDC (high voltage direct current) project will link two new hydropower plants in northwestern Brazil with São Paulo, the nation’s main economic hub. At a length of more than 2,500 kilometers (1,553 miles), it will be the longest electric transmission link in the world.

How much of the world’s population has no access to electricity?

  • 5 percent
  • 10 percent
  • 20 percent
  • 30 percent

About 1.3 billion people, or 20 percent of the world’s population, are living without any access to electricity in 2012, according to the International Energy Agency.





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