chapter 8- electromagnetic waves

Question 1

electromagnetic spectrum

Answer 1

in order from longest wavelength to shortest wavelength:
-Radio
-microwaves
-inferred
-visible light
-ultraviolet radiation
- X- rays and gamma rays

Question 2

infrared radiation

Answer 2

-the hotter the object, the more infrared radiation it emits
- it is absorbed by the skin–> it can burn or kill the skin cells, since it heats up the cells

Question 3

infrared uses

Answer 3

-optical fibres
-remote control handsets
-infrared scanners
-infrared cameras
-heating and cooking
-night vision

Question 4

microwaves

Answer 4

-used for communications
e.g. satellite TV, since the microwaves can pass through the earths atmosphere and reach satellites above earth
-also used to carry mobile phones signals
-heating food

Question 5

radio waves

Answer 5

-used for radio and TV broadcasting, radio communications and mobile phone calls
-astronomy

Question 6

the shorter the wavelength

Answer 6

-the more info they carry
-the shorter the range –> increasing absorption by the atmosphere
-the less they spread out –> they diffract less

Question 7

optical fibres

Answer 7

very thin fibres, used to transmit signals by light and infrared radiation
- carry more info than radio and microwave communications
- more secure than radio and microwaves communications

Question 8

ultraviolet radiation

Answer 8

-smaller than visible lights wavelength
-carries more energy

Question 9

X-rays and gamma rays similarities

Answer 9

-can damage living tissue when they pass through it
-carry much more energy per second –> short wavelength

Question 10

X-rays and gamma rays differences

Answer 10

-gamma rays are produced by radioactive substances when unstable nuclei releases energy
-gamma rays have a shorter wavelength
-X-rays are produced in an X-ray tube

Question 11

using gamma radiation

Answer 11

-killing harmful bacteria in food
-sterilising surgical instruments
-killing cancer cells

Question 12

X- rays uses

Answer 12

-make images and CT scans
- destroy tumors at or near the body surface
-killing cancerous cells
-security scanners

Question 13

black body radiation

Answer 13

range of electromagnetic radiation emitted by an object at a particular temperature

Question 14

ultraviolet radiation uses

Answer 14

-security markings
-sterilising water

Question 15

properties of x rays

Answer 15

-they affect a photographic film in the same way as light
-absorbed strongly by metal and bone
-transmitted by healthy tissue

Question 16

dark, matt surfaces are..

Answer 16

-good absorbers
-good emitters

Question 17

light, shiny surfaces are…

Answer 17

-poor absorbers
-poor emitters
-good reflectors of infared radiation

Question 18

properties of electromagnetic waves

Answer 18

-transverse
-can travel through a vacuum
-they transfer energy
-they travel at all the same speed in a vacuum

Question 19

the higher the temperature of the object

Answer 19

-the more infared radiations that is emitted and the higher the frequency of the infared radiation emitted

Question 20

visible light uses

Answer 20

-vision
-photographs/videos
-fibre optic communications

Question 21

dangers of infared waves

Answer 21

-skin burns

Question 22

dangers of visible light

Answer 22

eye damage

Question 23

dangers of ultraviolet waves

Answer 23

-eye damage
-sunburn
-skin cancer

Question 24

dangers of x rays

Answer 24

-kills cells
-mutations
-cancer

Question 25

dangers of gamma rays

Answer 25

-kills cells -genetic mutations -cancer

Question 26

dangers of microwaves

Answer 26

-possible heat damage to soft tissue and internal organs

Question 27

the shorter the wavelength...

Answer 27

the more ionising the radiation

Question 28

what are x rays absorbed by

Answer 28

-metal -bones