P6 Waves - Uses of Electromagnetic Waves

A man is wearing mirrored sunglasses. Anyone looking at him can see their reflection in the glasses but cannot see his eyes. The man can still see through the glasses. State what happens to the light as it passes from the surroundings to the mirrored sunglasses. It is...

• Reflected
• Absorbed
• Transferred

Give TWO reasons why radio waves are used for communication.

• Some radio waves can reflect off part of the Earth's atmosphere allowing them to travel long distances.
• They are not very hazardous.
• They carry sound waves over long distances.

Give TWO uses for microwaves.

• Cooking
• Satellite communication.
• Sterilisation.
• Medicine
• Blue-tooth

How do microwaves cook food?

• Microwaves are absorbed by water and this causes water in the food to heat up. This cooks the food.
• Microwaves are transmitted by water and this causes water in the food to heat up. This cooks the food.

Why are microwaves used for satellite communication?

• They carry signals clearly through the Earth's atmosphere.
• They are transmitted through water molecules in the Earth's atmosphere.

Give ONE use for radiowaves

• Cooking
• Satellite communication.
• Sterilisation.
• Communication
• Blue-tooth

Give THREE appications for infrared radiation

• Electric heaters
• Cookers for food
• Infrared cameras
• Motion sensors used at night.
• Steralising medical equipment

Why is infrared radioation used for heating and cooking food.

• Infrared is easily absorbed by objects causing them to heat up.
• Infrared is easily transmitted through objects causing them to heat up.

Give TWO uses for infrared cameras.

• To see things in the dark
• To analyse the thermal properties of an object.
• To detect movement in the dark

Give ONE use of visible light.

• Fibre optic communcations (light travels along fibres made of glass or plastic).
• To see things in the dark.
• To steralise medical equipment.