topic 6

Question 1

what is the effect of each type of radiation based on

Answer 1

how much energy the wave transfers

Question 2

what happens when low frequency waves pass through soft tissue

Answer 2

they don’t transfer much energy and so mostly pass through soft tissue without being absorbed

Question 3

why are high frequency waves dangerous

Answer 3

because they all transfer lots of energy and so can cause lots of damage

Question 4

what is UV radiation damaging to

Answer 4

-surface cells, which can lead to sunburn and cause skin to age prematurely

Question 5

what are the serious effects of uv radiation

Answer 5

it can cause blindness and an increased risk of skin cancer

Question 6

give 2 examples of ionising radiation

Answer 6

gamma rays and X-rays

Question 7

gamma and x-rays carry enough energy to do what …

Answer 7

knock electrons off of atoms

Question 8

how is ionising radiation dangerous

Answer 8

it can cause gene mutation, cell destruction or even cancer

Question 9

what is radiation dose measured in

Answer 9

sieverts

Question 10

what is radiation dose

Answer 10

a measure of the risk of harm from the body being exposed to radiation

Question 11

what does the risk of radiation dose depend on

Answer 11

the total amount of radiation absorbed and how harmful the type of radiation is

Question 12

what are optic fibres

Answer 12

thin glass or plastic fibres that can carry data from telephones or computers over long distances as pulses of visible light

Question 13

how do optic fibres transmit data

Answer 13

by using visible light

Question 14

how does light rays work by

Answer 14

reflection- the light rays are bounced back and forth until they reach the end of the fibre

Question 15

why is visible light used in optic fibres

Answer 15

because it is easy to refract light enough so that it remains in a narrow fibre

Question 16

how do you get a clearer x-ray image, what does it depend on

Answer 16

it depends on the amount of x-ray radiation that is absorbed through the body

Question 17

what is x-rays and gamma rays used to treat

Answer 17

cancer

Question 18

what can gamma radiation also be used as

Answer 18

a medical tracer- this is where a gamma-emitting source is injected into the patient, and its progress is followed around the body

Question 19

how do radiographers keep safe from x-ray and gamma radiation

Answer 19

they stand behind a lead screen, wear lead aprons or leave the room

Question 20

what do fluorescence light generate and what is it re-emitted as

Answer 20

UV radiation- which is absorbed and re-emitted as visible light by a layer of phosphorus on the inside of a bulb

Question 21

why are fluorescence lights good

Answer 21

because they are energy-efficient and and can be used when light is needed for a long period of time

Question 22

what can security pens used to do

Answer 22

used to mark properties with names and can only glow under UV light

Question 23

what is uv radiation produced by

Answer 23

the sun

Question 24

what does communication to and from satellites use

Answer 24

microwaves

Question 25

if you want to use microwaves for communication what do the microwaves need to pass through

Answer 25

the earth's watery atmosphere

Question 26

in microwave ovens what do the microwaves need to be absorbed by

Answer 26

water molecules in the food

Question 27

absorbing IR radiation causes objects to what ...

Answer 27

become hotter

Question 28

what can IR radiation be used for

Answer 28

-cameras to see detect houses or objects and electric heaters

Question 29

what are EM waves made up of

Answer 29

oscillating electric and magnetic fields

Question 30

what type of current is made up of oscillating charges

Answer 30

alternating currents

Question 31

as charges oscillate, what do they produce

Answer 31

oscillating electric and magnetic fields or electromagnetic fields

Question 32

what are radio waves mostly used for

Answer 32

communication

Question 33

when waves travel through a medium what happens to the particles

Answer 33

the particles of the medium oscillate and transfer energy between each other

Question 34

what is the wavelength

Answer 34

the distance between the trough of one wave and the trough of wave next to it

Question 35

what is the frequency

Answer 35

the number of complete waves passing a certain point per second

Question 36

describe the oscillations in transverse waves

Answer 36

they are perpendicular (at 90 degree angles) to the direction of energy transfer

Question 37

give 3 examples of transverse waves

Answer 37

- all electromagnetic waves - ripples and waves in water - a wave on a string

Question 38

describe the oscillations in longitudinal waves

Answer 38

the oscillations are parallel to the direction of energy transfer

Question 39

give an example of a longitudinal wave

Answer 39

a sound wave in the air

Question 40

name the 3 things that can happen when a wave meets a boundary between 2 materials

Answer 40

1) the wave is ABSORBED by the second material 2) the wave is TRANSMITTED through the second material 3) the wave is REFLECTED

Question 41

electromagnetic waves are what type of waves

Answer 41

transverse waves

Question 42

what are electromagnetic waves vibrations of

Answer 42

electric and magnetic fields , this means that they can travel through a vacuum (space)

Question 43

from the start of the EM wave spectrum, describe the frequency and the wavelength

Answer 43

it has a long wavelength and low frequency

Question 44

at the end of the EM wave spectrum, describe the frequency and the wavelength

Answer 44

it has a short wavelength and high frequency

Question 45

what is refraction

Answer 45

when waves hit a boundary at an angle and change direction

Question 46

what happens when a wave crosses boundary between 2 materials

Answer 46

it changes speed

Question 47

what is the optical density of a material

Answer 47

a measure of how quickly light can travel through a material

Question 48

what is wave speed

Answer 48

the speed at which the wave moves through the medium (i.e. the speed at which energy is transferred)

Question 49

1Hz=

Answer 49

1 wave per second

Question 50

wave speed (m/s)=

Answer 50

frequency (Hz) X wave length (m)

Question 51

how can we make sure that the results are accurate for reaction times (3)

Answer 51

- take results and remove any results that are anomalous -calculate mean value - more people with timers

Question 52

how can we reduce the problem of pressing the timer at correct times

Answer 52

by increasing the distance between the 2 people

Question 53

what happens to waves when they change direction

Answer 53

it changes speed

Question 54

when light passes from air into glass what happens

Answer 54

the velocity of light decreases (the light waves slow down.) this causes the direction of the wave to change

Question 55

when waves slow down they ...

Answer 55

bend towards the normal

Question 56

what happens when ... | waves pass from the glass back to the air

Answer 56

their velocity increases- the light waves speed up

Question 57

what happens when waves speed up

Answer 57

they bend away from the normal

Question 58

when can refraction happen

Answer 58

when any wave changes speed as it passes from one medium to another