Bon the Screen, Draw the Shadow That the Heart Would Form

HELP

1Copy the diagram below.

aContinue the two light rays to show where they would hit the screen.

bOn the screen, draw the shadow that the heart would form.

cPut an arrow onto each ray, to show which way the light is travelling.

2aImagine that you had a pinhole camera where the screen is. Draw the shape that would form on the small screen inside the camera.

bWhat do we call the picture inside the camera?

3aWhen you switch on a light do you:

Asee the light after about one second?

Bsee the light after about 2 seconds?

Csee the light immediately?

bWhat does this tell you about the speed of light?

4When a building is on fire it can be seen from anywhere. Explain why this is so.

This worksheet may have been altered from the original on the CD-ROM.

CORE

5John is experimenting with solar cells. This diagram shows how hehas set up a solar cell to drive an electric fan.

aDraw an energy transfer diagram showing all the energy transfers, from the light leaving the lamp to the fan spinning.

bExplain why John can see the lamp.

cExplain why John can see the solar cell.

6aThe speed of light is 300 000 km/s. How far will light travel in half a second?

bHow far will it travel in 5 seconds?

EXTENSION

7During autumn we can see both Jupiter and Venus, from the Earth, at the same time.

aVenus is often the brightest object in the night sky but it is much smaller than Jupiter. Give three reasons why Venus is always brighter than Jupiter.

biJupiter has four bright moons that can be seen with a telescope. Explain why it is possible to see them.

iiJupiter’s moons have different brightnesses, even though they are all about the same distance from the Earth. Suggest a reason for the differences.

8The Earth is 150 million kilometres from the Sun. Mars is 225 million kilometres and Jupiter is 780 million kilometres away from the Sun.

Light takes 8.5 minutes to travel from the Sun to the Earth.

aHow long does it take for light from the Sun to reach Mars? Show your working.

bHow long does it take for light from the Sun to reach Jupiter?

cHow long does it take reflected light, from Jupiter, to reach the Earth?Show your working.

This worksheet may have been altered from the original on the CD-ROM.