Department of Energy

Quiz: Test Your Lighting IQ

March 23, 2016

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Quiz: Test Your Lighting IQ

How bright are you when it comes to lighting trivia? Test your knowledge with this fun quiz!

1. How do LEDs generate light?

By heating up filament

By moving electrons in compound semiconductors

By ionizing mercury vapor in a glass tube

By moving electric current through a tube containing gas


2. How is light bulb brightness measured?





Lumens measure how much light you are getting from a bulb. More lumens means it's a brighter light while fewer lumens means it's a dimmer light.

3. Who patented the incandescent light bulb?

David Melville

Nikola Tesla

Thomas Edison

Emmett Wiley

Thomas Edison first patented the incandescent light bulb in 1879 but long before that, British inventors were demonstrating that electric light was possible with the arc lamp.

4. How much money can you save a year by switching out your five most frequently used lights with ENERGY STAR bulbs?





Changing five of your most frequently used lights with ENERGY STAR bulbs can save you $75 a year on energy costs.

5. Which of the following is NOT true of LEDs?

The cost of LEDs has declined nearly 90 percent since 2008

LEDs are white light sources

LEDs have many benefits including energy savings potential, lower costs and improved performance

LEDs reduce the need for reflectors and diffusers

Unlike incandescent lamps, LEDs are not inherently white light sources. Instead, LEDs emit nearly monochromatic light, making them highly efficient for colored light applications such as traffic lights and exit signs.

6. What's the main reason why LEDs are more energy efficient compared to other lighting options?

The process they use to convert electricity into light is more effective

They are made of higher quality materials

They use alternating current instead of direct current

They absorb less heat

LEDs can convert electricity into light more effectively than incandescents or fluorescents. This is due to LED semiconductors, which create more photons per unit of input energy.

7. What does illumination refer to?

The wavelength used to generate light

The ratio of light produced to energy consumed

The color patterns used in lighting

The distribution of light on a horizontal surface

Illumination is the distribution of light on a horizontal surface. The purpose of all lighting is to produce illumination.

8. How much less energy do LEDs use compared to traditional incandescent bulbs?

50 percent

80 percent

10 percent

90 percent

LEDs use 80 percent less energy than traditional incandescent bulbs and last about 25 times longer. LEDs are projected to reach over 80 percent of all lighting sales by 2030, which could save Americans $26 billion per year in electricity costs, while cutting America's lighting electricity use by nearly half.

9. Which of the following is NOT a type of lighting control?





Use of lighting controls like dimmers, photosensors and timers allow you to automatically turn lights on and off as needed, helping you save energy and money.

10. What year was the first visible-spectrum LED invented?





The first visible-spectrum LED was invented by Nick Holonyak, Jr., while working for GE in 1962. Since then, the technology has rapidly advanced thanks to research and development by the Energy Department and private sector partners. This has dramatically lowered costs, making LEDs a viable lighting solution for all.

11. What does daylighting mean?

Using light-reflective material outside buildings to keep heat and light from entering the building

Using windows and skylights to bring sunlight into buildings

Using windows, walls and floors to collect, store and distribute solar energy

Using landscaping to provide shade for buildings in the summer

Daylighting is the use of windows and skylights to bring sunlight into buildings. Daylighting in businesses and commercial buildings can result in big savings on energy bills.

12. Incandescent bulbs lose what percent of their energy as heat?

82 percent

95 percent

90 percent

70 percent

Unlike incandescent bulbs -- which release 90 percent of their energy as heat -- LEDs use energy far more efficiently with little wasted heat.

Your Score:

A world without lighting would be... well, pretty dark. This important invention brightened our lives -- making cities, homes and buildings safer and workers more productive. But how much do you know about the lighting technology that you count on every single day?

Test your knowledge with our latest quiz. For even more illumination, explore Energy Saver for lighting basics and tips. Want to geek out about lighting tech? Learn more from the Energy Department’s Solid State Lighting Program.