Sources of Light

What is the primary source of light on Earth?

• Fire

• Sun

• Moon

• Stars

Name a natural source of light other than the Sun.

• Lanterns

• Stars

• Moonlight

• Fireflies

What type of light source is a candle?

• Fluorescent

• LED

• Incandescent

• Halogen

Which type of light source produces light by passing an electric current through a filament?

• LED light bulb

• Incandescent light bulb

• Fluorescent light bulb

• Halogen light bulb

What is the process by which light is produced in a fluorescent light bulb?

• Heat generated by the bulb's filament

• Chemical reaction between gases inside the bulb

• Electric current passing through mercury vapor and exciting phosphor coating

• Bioluminescent bacteria coating the inside of the bulb

What type of light source is a campfire?

• Fluorescent light source

• LED light source

• Ultraviolet light source

• Incandescent light source

What type of light source is a flashlight?

• Mobile light source

• Stationary light source

• Portable light source

• Immobile light source

Which type of light source emits light due to the flow of electric current through a gas or vapor?

• Hydroelectric lamp

• Wind-powered lamp

• Gas-discharge lamp

• Solar lamp

What type of light source is a smartphone screen?

• Backlit or OLED light source

• Incandescent light source

• LED light source

• Fluorescent light source

What type of light source is a lightning bolt?

• Artificial light source

• Natural light source

• Bioluminescent light source

• Man-made light source