Properties Of Waves

Question 1

How to generate an electromagnetic wave

Answer 1

When atoms heated electrons move from one energy level to a higher one
= when electron returns to original level it generates an electromagnetic wave
(Change to the atom has generated an electromagnetic wave)

Question 2

Second way of generating an electromagnetic wave

Answer 2

Change to the nucleus eg gamma rays
- gamma rays can be emitted from nucleus of radioactive atoms
- once ray emitted nucleus has less energy than it had at start

Question 3

Properties of electromagnetic waves

Answer 3

• when waves absorbed can cause changes to atoms
• waves can be emitted and absorbed over a wide frequency range from radio waves to gamma rays

Question 4

Effects of ultraviolet rays

Answer 4

Increase risk of skin cancer
Cause skin to age prematurely

Question 5

Effects of x rays and gamma rays

Answer 5

Ionising radiation
= cause mitigation of genes
= increase risk of cancer

Question 6

What depends on damage caused by radiation

Answer 6

Type of radiation
Dose of radiation

Question 7

How to produce radio waves

Answer 7

When electrons oscillate in electrical circuits
= waves can be absorbed
= causes electrons in circuit to oscillate
= create an alternating current with same frequency as radio waves

Question 8

Uses of radio waves

Answer 8

Transmit radio and terrestrial TV signals

Question 9

Why do use radio waves

Answer 9

• travel long distances before being absorbed eg by building and trees
• can reflect off a layer of changes particles in atmosphere
  = allow us to send waves very long distances around the earth

Question 10

Uses of micro waves

Answer 10

Heating food
Communicate with satellites in space

Question 11

How do microwaves send satellites in space

Answer 11

Microwaves can pass through earths atmosphere without being reflected of refracted

Question 12

Uses of infrared and how

Answer 12

Emitted by electrical heaters
Cook food in ovens
= energy of infrared is easily absorbed by surface of objects
Infrared cameras

Question 13

Use of visible light and how

Answer 13

Communication using fibre optics
= can transmit pulses or light down fibres and use these to carry info
= carry telephone signals

Question 14

Use of ultraviolet

Answer 14

Energy efficient lightbulbs

Question 15

Why does ultraviolet carry more energy

Answer 15

Has a short wavelength

Question 16

How does ultraviolet absorb energy

Answer 16

Absorbed by internal surface of bulb and converted to visible light
= requires less energy than normal light bulb

Question 17

Uses of x rays and gamma rays

Answer 17

Medical imaging
= very penetrating
= can pass easily through body tissue