Topic 1 - Radiation And Treatment

Question 1

What are X-rays

Answer 1

High energy EM waves that get absorbed by dense materials

Question 2

Are X-rays ionising or non ionising

Answer 2

Ionising

Question 3

What can X-ray photographs diagnose

Answer 3

Bone fractures

Question 4

What does CAT scans stand for

Answer 4

Computerised axial tomography

Question 5

What do CAT scans produce

Answer 5

2D slice through the body

Question 6

What do CAT scans use

Answer 6

Intense beams of X-rays

Question 7

What can CAT scans do that x rays can’t

Answer 7

Image soft tissue as well as bones

Question 8

What do endoscopes use to see inside the body

Answer 8

Optical fibres

Question 9

What type of electromagnetic Ray do endoscopes use

Answer 9

Visible light

Question 10

What do endoscopes help to reduce the use of

Answer 10

Invasive surgery

Question 11

What frequency does ultrasound use

Answer 11

Above 20 kHz

Question 12

What can ultrasound be used for

Answer 12

Breaking down kidney stones into sand like particles
Pre natal scan of a foetus
Measuring the speed of blood flow

Question 13

What is radiation

Answer 13

Energy that originates from a source

Question 14

What does the intensity of radiation depend on

Answer 14

Distance from a source

What it’s passing through

Question 15

Unless passing through a vacuum some of the radiation will…..

Answer 15

Always be absorbed by the medium

Question 16

Intensity equals

Answer 16

Power divided by area

Question 17

Refraction is……

Answer 17

A change in direction caused by a change in speed

Question 18

If a wave hits a boundary along the norm….

Answer 18

It will not change direction

Question 19

What are the two main types of lenses

Answer 19

Converging and diverging

Or convex and concave

Question 20

Convex lense cause light rays to…..

Answer 20

Converge to a focus at the lens focal point

Question 21

Concave lens cause light rays to…

Answer 21

Spread out

Question 22

The focal point of a diverging lens is the point where………

Answer 22

Rays hitting the lens parallel to the axis appear to come from

Question 23

What are the three rules for refraction in a converging lens

Answer 23

An incident Ray parallel to the axis refracts through the lens and passes through the focal point on the other side

An incident Ray passing through the focal point before entering the lens will refract through the lens and travel parallel to the axis

An incident Ray passing through the centre of the lens will carry on in the same direction.

Question 24

At 2F the object will be……

Answer 24

Real, Inverted, same as object, at 2F

Question 25

An object between F and 2F will be....

Answer 25

Real, inverted, bigger than object, beyond 2F

Question 26

An object nearer than F will be

Answer 26

Virtual right way up, bigger than object and same side of the lens

Question 27

What are the three rules of a diverging lens

Answer 27

An incident Ray parallel to the axis refracts through the lens travels in line with the focal point An incident Ray passing towards the focal point refracts through the lens and travels parallel to the axis An incident Ray passing through the centre of the lens carries on in the same direction

Question 28

An diverging lens always produces....

Answer 28

A virtual image that is the right way up, smaller and on the same side of the lens

Question 29

The power of a converging lens is always

Answer 29

Positive

Question 30

The power of a diverging lens is always

Answer 30

Negative

Question 31

Power of lens equals

Answer 31

1 divided by focal length

Question 32

What does the iris do

Answer 32

Coloured part of the eye Made up of muscles that control the size of the pupil Controls how much light enters the eye

Question 33

What does the cornea do

Answer 33

The transparent window with a convex shape it does most of the eyes focusing

Question 34

How is light focused on by the retina

Answer 34

By the lens and the cornea working together

Question 35

What kind of power does the cornea have

Answer 35

Fixed

Question 36

What is the lens controlled by

Answer 36

Ciliary muscles

Question 37

What is the retina covered in

Answer 37

Light sensitive cells

Question 38

What is the furthest point your eye can see comfortable

Answer 38

Infinity

Question 39

What is the nearest point your eye can see

Answer 39

25cm

Question 40

Short sighted people cant...

Answer 40

Focus on objects that are far away

Question 41

What are x rays used for

Answer 41

Medical imaging

Question 42

Why are some people short sighted

Answer 42

Cornea and lens too powerful or eyeball is too long | Ciliary muscles can't relax enough

Question 43

What can't long sighted people do

Answer 43

Can't focus on things close up

Question 44

Why are some people long sighted

Answer 44

Cornea or lens too weak Eyeball is too short Ciliary muscles can't contract enough

Question 45

In long sighted people the I shed of near object are....

Answer 45

Brought into focus behind the retina

Question 46

How do you fix short sightedness

Answer 46

Diverging or concave lens | Brought into focus on the retina

Question 47

How can you correct long sightedness

Answer 47

Convex lens | Brought into focus earlier

Question 48

How else can you fix a vision defect

Answer 48

Contact lenses which compensate the fault of the eye shape Laser eye surgery which permanently changed the shape of the cornea

Question 49

What is Snells law

Answer 49

When an incident Ray passed into a material the angle of incidence angle of refraction and refractive index are related by this formula n = sin i ------------- sin r

Question 50

What is the critical angle

Answer 50

90 degrees

Question 51

If the angle of incidence is less than the critical angle.....

Answer 51

Most of the light passes out but a little bit of it is internally reflected

Question 52

If the angle of incidence is equal to the critical angle

Answer 52

The emerging Ray comes out along the surface there's quite a bit of reflection

Question 53

If the angle of incidence is greater than the critical angle then

Answer 53

No light comes out | Total internal reflection

Question 54

You can find critical angles using...

Answer 54

Snells law

Question 55

Nr is ......

Answer 55

The refractive index of the stuff the lights travelling towards

Question 56

Ni is

Answer 56

The refractive index of the material the light starts from

Question 57

How do optical fibres work

Answer 57

Carry visible lights and can be used in medical diagnosis and communications technology Work because of total internal reflection light waves are reflected off the sides of a thin inner core of plastic or glass Reflected repeatedly until it reaches the other end