Use of Em waves.

Question 1

Radio waves:

Answer 1

• Used to transmit both radio signals and terestrial tv signals (this is not sattelite or cable tv and is recieved using an aerial).

Question 2

Why are radio waves used?

Answer 2

• Travel long distances, before being aborbed by trees and and buildings e.g
• Longer radio waves can also spread out between hills (defraction).
• Can also reflect off a layer of charged particles in the atompshere (ionospeher) allows us to send them in long distances.

Question 3

Microwaves:

Answer 3

• Used to heat food as most foods contain alot of water molecules and water molecules are absorbe the energy of microwaves.
• Energy causes the temperature of the food to increase.

Used to communicate with satelties in space as microwaves can pass trhough the earths atmopshere without being reflected or refracted.

Question 4

Infrared:

Answer 4

• Emmited by electrical heaters and and is used to cook food in ovens.
• Energy in infrared is easily abosbred by thr surface of an obkect.
• Imfrared from the heater is absorbed by the objects in a room, make sit warmer.
• ## also used in infrared cameras to check heat loss for example.

Question 5

Visible Light:

Answer 5

• Important use is for communication using fibre optics
• ## Visible light has a short wavelength it can carry a great deal of information.

Question 6

Ultra Violet:

Answer 6

• Used for energy efficent lightbubls.
• ## Short wavelength- carries more energy than visible light.

Question 7

Xrays and Gamma Rays:

Answer 7

• Used in medical imaging.
• Xrays= produces an image of bones.
  Gamma Rays= detect cancers.
• Very penetrative.
• pass easily trhough boddy tissues.
• Xrays are absorbed by bones.
• and medical treatments.