World Book Trivia Quiz For Kids---light-australia

1. Electric power is measured in what type of unit?

Mph

Watts

Inches

Electric power is measured in units called watts. For example, it takes 100 watts of electric power to operate a 100-watt light bulb. The world's power plants produce billions of watts at any given time.

Explanation

Electric power is measured in units called watts. For example, it takes 100 watts of electric power to operate a 100-watt light bulb. The world's power plants produce billions of watts at any given time.

2. The speed of light in empty space is always the same.

True

False

Scientists measure the wavelength, brightness, and speed of light. The speed of light in empty space is always the same. In space, light travels at 186,282 miles (299,792 kilometers) per second.

Explanation

Scientists measure the wavelength, brightness, and speed of light. The speed of light in empty space is always the same. In space, light travels at 186,282 miles (299,792 kilometers) per second.

3. Which of the following can a prism NOT do?

Change direction of light

Break up light into colours of the rainbow

Block light from coming through

A prism is a thick, three-sided piece of glass or a kind of rock called quartz. It can change the direction of light. It can also break light up into the colours of the rainbow.

Explanation

A prism is a thick, three-sided piece of glass or a kind of rock called quartz. It can change the direction of light. It can also break light up into the colours of the rainbow.

4. Why do rainbows appear?

Sunlight shines on raindrops

Leprechauns create them

Sunlight reflects off clouds

Rainbows are curved bands of coloured light that appear in the sky. We see rainbows when the sun shines on raindrops. Sometimes both ends of the rainbow seem to touch the ground.

Explanation

Rainbows are curved bands of coloured light that appear in the sky. We see rainbows when the sun shines on raindrops. Sometimes both ends of the rainbow seem to touch the ground.

5. A light-year is the distance that light travels in one year.

True

False

A light-year is the distance that light travels in one year. The light-year is used by scientists called astronomers. They use the light-year to describe the huge distances between stars, galaxies, and other objects in space.

Explanation

A light-year is the distance that light travels in one year. The light-year is used by scientists called astronomers. They use the light-year to describe the huge distances between stars, galaxies, and other objects in space.

6. What colour are the shortest light waves we can see?

Violet

Red

Green

The violet waves are the shortest waves we can see, and red waves are the longest.

Explanation

The violet waves are the shortest waves we can see, and red waves are the longest.

7. Which type of light bulb uses a filament?

Fluorescent

Incandescent

One kind of light bulb is an incandescent bulb. It passes electricity through a metal wire called a filament. The filament heats up and glows. It sits inside a glass bulb. Fluorescent bulbs pass electricity through special gases in a glass tube. The gas gives off energy. The energy is invisible. But it makes a coating on the glass glow brightly.

Explanation

One kind of light bulb is an incandescent bulb. It passes electricity through a metal wire called a filament. The filament heats up and glows. It sits inside a glass bulb. Fluorescent bulbs pass electricity through special gases in a glass tube. The gas gives off energy. The energy is invisible. But it makes a coating on the glass glow brightly.

8. When did gas lamps become popular?

1600's

1800's

2000's

Gas lamps were used in the 1800's. The gas was piped into the lamp. It burned as it rushed out of a small opening and mixed with the air. Today, gas lamps are sometimes used by campers. Such lamps provide light in places with no electric power.

Explanation

Gas lamps were used in the 1800's. The gas was piped into the lamp. It burned as it rushed out of a small opening and mixed with the air. Today, gas lamps are sometimes used by campers. Such lamps provide light in places with no electric power.

9. What are light waves called that are too long to be seen called?

Ultraviolet

Infrared

Invisible

Waves too short to be seen are called ultraviolet rays. They cause sunburn and suntan. Waves too long to be seen are called infrared rays. They cause the warming we feel in sunlight.

Explanation

Waves too short to be seen are called ultraviolet rays. They cause sunburn and suntan. Waves too long to be seen are called infrared rays. They cause the warming we feel in sunlight.

10. All light comes from atoms.

True

False

Some light, such as sunlight, comes from nature. Other light comes from things people make, such as lamps. But all light comes from atoms >, tiny particles of matter that make up everything in the universe.

Explanation

Some light, such as sunlight, comes from nature. Other light comes from things people make, such as lamps. But all light comes from atoms >, tiny particles of matter that make up everything in the universe.