Topic 1- Radiation and Treatment

Question 1

both ionising and non- ionising radiation are used in

Answer 1

medicine

Question 2

X-rays are used for

Answer 2

medical imaging

Question 3

x-rays are high energy and get absorbed by

Answer 3

dense materials like bone and metal

Question 4

X-rays have a

Answer 4

health risk

Question 5

CAT scans use

Answer 5

X-rays

Question 6

CAT scans produce an image of a

Answer 6

2D slice through the human body

Question 7

CAT scans are different from usual X-rays because they can produce an image of

Answer 7

soft tissue too

Question 8

Endoscopes use

Answer 8

optical fibres

Question 9

visible light is

Answer 9

non-ionising

Question 10

endoscopes are good because it prevents

Answer 10

invasive surgery

Question 11

ultrasound has a frequency of

Answer 11

more than 20000 Hz

Question 12

ultrasound in

Answer 12

non-ionising

Question 13

ultrasound can be used for

Answer 13

breaking down kidney stones, pre-natal scanning, measuring the speed of blood flow

Question 14

radiation is energy that

Answer 14

originates from a source

Question 15

Power=

Answer 15

I x A

Question 16

intensity of radiation depends on

Answer 16

distance from source

Question 17

intensity of radiation also depends on

Answer 17

what i t is passing through

Question 18

the more dense the medium,

Answer 18

the more radiation will be absorbed

Question 19

refraction is a change in direction caused by

Answer 19

a change in speed

Question 20

convex lenses

Answer 20

converge light rays

Question 21

concave lenses

Answer 21

diverge light rays

Question 22

remember how to do ray tracing diagrams

Answer 22

yes

Question 23

if the object is at 2F

Answer 23

real image, inverted,same size as object at 2F

Question 24

if the object is between F and 2 f

Answer 24

real image, inverted, bigger and further than 2F

Question 25

if the object is closer than F

Answer 25

virtual image, right way up, on same side, and bigger

Question 26

power of lens=

Answer 26

1/focal length

Question 27

1/f=

Answer 27

1/u + 1/v

Question 28

for the eye you need to know the

Answer 28

basic structure

Question 29

the iris is

Answer 29

the coloured part of the eye

Question 30

the pupil is

Answer 30

the hole in the middle of the iris

Question 31

the cornea is

Answer 31

transparent

Question 32

the light is focused on the

Answer 32

retina

Question 33

the lens is controlled by

Answer 33

the ciliary muscles

Question 34

the far point is

Answer 34

the furthest distance that the eye can focus comfortably

Question 35

the near point is

Answer 35

the closest distance the eye can focus on

Question 36

on average, distances are

Answer 36

infinity, and 25 cm

Question 37

short sighted people can't focus on

Answer 37

distant objects

Question 38

long sighted people can't focus on

Answer 38

close objects

Question 39

short sight can be corrected with

Answer 39

diverging lenses

Question 40

long sight can be corrected with

Answer 40

converging lenses

Question 41

sight can be corrected with

Answer 41

contact lenses or laser eye surgery

Question 42

treatment for vision defect depends on

Answer 42

patient

Question 43

every transparent material has

Answer 43

a refractive index

Question 44

snell's law says

Answer 44

n= sin i/ sin r

Question 45

total internal relfection depends on

Answer 45

angle of incidence

Question 46

greater than critical angle means that

Answer 46

no light comes out and all is totally internally reflected

Question 47

critical angles can be found using

Answer 47

snell's law

Question 48

sin C=

Answer 48

refractive index of where the light is travelling to/ refractive index of where the light starts from