More Uses Of Electromagnetic Waves

Question 1

what is visible light in relation to humans

Answer 1

its is the light that we can see

Question 2

how do traditional cameras create photographs

Answer 2

• old cameras such as photographic film

- would react to light to form an image

Question 3

how do digital cameras form images

Answer 3

• they contain image sensors
• which detect visible light and generate an electrical signal
• the signal is then converted into an image
• that can be stored digitally or printed

Question 4

what is flourescence

Answer 4

• a property of certain chemicals
• where ultraviolet light is absorbed
• and visible light is emitted

Question 5

why do fluorescent colours look bright

Answer 5

because they are emitting light

Question 6

what are the three ways in which ultraviolet lights are used

Answer 6

• flourescent lights
• security pens
• bank notes

Question 7

how do flourescent lights use ultraviolet light

Answer 7

• they use UV to emit visible light

- they are energy efficient so they are good to use when light is needed for long periods of time

Question 8

how do security pens use ultraviolet light

Answer 8

• they can be used to mark property such as laptops
• under UV light the ink will glow
• but it is invisible otherwise
• helping to identify stolen property

Question 9

how do bank notes use ultraviolet light

Answer 9

• bank notes and passports use a similar technique to detect forgeries
• genuine notes and passports have special markings that will only show up under UV light

Question 10

how is ultraviolet radiation used to sterilise water

Answer 10

• it kills bacteria in the water
• making it safe to drink
• gamma rays are also used in a similar way

Question 11

what is the main use of x-rays that we have

Answer 11

• they can be used to view the internal structure of objects and materials
• including our bodies

Question 12

why are you able to take x-ray photographs and how do do it now

Answer 12

• you can take photographs because they affect photographic film the same way that visible light does
• but x-ray images are usually formed electronically these days

Question 13

what do radiographers take x-ray images to do

Answer 13

• help doctors diagnose broken bones
• x-rays are transmitted by flesh
• but are absorbed by denser material like bones or metal

Question 14

how do you produce an x-ray image

Answer 14

• x-ray radiation is directed through the object or body onto a detector plate
• the brighter bits of the image are where fewer x=rays get through
• producing a negative image as the plate starts of all white

Question 15

what are the different ways that gamma rays are used

Answer 15

• sterilisation
• medical imaging like in PET scans
• cancer treatments

Question 16

if gamma rays can be used to sterilise medical instruments, what other thing can they be used to sterilise

Answer 16

• food can be sterilised in the same way to kill microbes
• this keeps the food fresher for longer without having o freeze it , cook it or preserve it in some other way
• and its perfectly safe to eat

Question 17

how are gamma rays specifically used for in medical images

Answer 17

• they are used to make medical tracers

- which are used to detect cancer

Question 18

how is gamma radiation used in cancer treatments, not detection

Answer 18

• radiation is targeted at cancer cells to kill them

- doctors have to be careful to minimise the damage to healthy cells when treating cancer like this