Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Physics 2 And 3 > P3 > Flashcards

P3 Flashcards

(56 cards)

Start Studying
1
Q

What are X rays like

A

They are part of the electromagnetic spectrum
They have a high frequency and a very short wavelength
They have high energy and can cause ionisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the uses of X rays

A

Can form an image on an X Ray plate or with a CCD (electronic image)
Can take shadow pictures of bones to detect breaks and fractures
Can scan to detect problems with soft tissue e.g. Disease
Used for killing cancer cells in radiotherapy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the precautions

A

Only use if necessary and use as low a power as possible
Use a focuses beam during treatments so as not to expose areas of the body not being treated or examined
Technicians should take the X rays from behind a screen or wear lead clothing
Technicians should wear detection badges, which measure their exposure over time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is ultrasound

A

Sound waves of frequencies greater than 20 000Hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What happens when and ultrasonic waves pass from one medium into another

A

They are partly reflected at the boundary. The reflected waves are usually processed to produce a visual image on a screen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do you measure how far away the boundary is

A

The time taken for the ultrasonic waves to be reflected

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the use of ultrasounds in medicine

A

The mains use is in prenatal scans but it can also be used for other scans e.f. Detection of gesticulating cancer

It can also be used to break up kidney stones which can then be passed out of the body in urine. This saves having to operate on their patients kidneys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does an ultrasound on a baby work

A

An ultrasound pulse is sent into the body and gets reflected back at different changes of density. These reflected waves are detected and used to form a picture of the foetus. Because ultrasound is non ionising it is safer to use use than X rays

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How do you locate a flaw or crack in a block of metal

A

Some ultrasound waves are reflected back by the flaw or crack within the structure. The time taken for the reflected wave to return is used to calculate the location of the crack

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Best to worse image quality of scanning methods

A

CT scans
X rays
Ultrasound

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Most to least radiation exposure

A

CT scans
X rays
Ultrasounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is refraction

What does it depend on

A

The change of direction of light as it passes from one medium to another

The refractive index of the material and the angle of incidence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a lens

What are the two types of lens

A

A piece of transparent material that refracts light rays

Diverging
Converging

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the focal length

A

The distance from the lens to the principal focus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a diverging (concave) lens like

A

Thin at the centre
The rays of light are refracted outwards so that they appear to have came from one point, the focus
The image produced by a diverging lens is virtual and upright

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a converging (convex) lens like

A

Thick at the centre

The light rays are refracted inwards to converge at one point called the focus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does the image produced by a converging lens depend on

A

The distance of the object from the lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the image like if the distance from the object to the lens is longer than the distance from the lens to the focal point in a converging lens

When is this type of lens used

A

Real image
Inverted

In cameras

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the image like if the distance from the object to then lens is less than the distance from the lens to the focus point in a converging lens

When is this type of lens used

A

Virtual image
Upright
Enlarged
Seems to be formed on the same side of the lens

In magnifying glasses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does the adjustable convex lens do

A

Focuses on the image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why does someone need glasses

A

Their lenses are unable to focus the image correctly on the retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does the retina do

What do lenses do

What does the cornea do

What does the pupil do

Why does the iris do

A

Focuses images

Focuses the images

Protects the eye and begins to focus the light

Light enters the eye here

Adjusts to alter the amount of light entering the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What do suspensory ligaments do

What do ciliary muscles do

Study These Flashcards
A

Connect the lens to the ciliary muscles

Contract and relax to alter the shape of the lens so the eye can focus on objects at different distances

24
Q

In a camera:
What allows light to enter

What focuses the light

Adjusts focus for different distances

Controls amount of light entering

Forms the image

Study These Flashcards
A

Aperture

Convex lens

Lens moves closer or further away from the film

Diaphragm/ aperture stop changes the aperture size

Photographic film or CCD chip

25
What so the range of vision in a normal eye
Between the near point ( around 25cm) and the far point (infinity)
26
What is the eye like if it's short sighted How do you correct short sightedness
The eyeball is too long or the lens is too fat. This means that near object are in focus, but distant objects are focused in front of the retina Diverging lens
27
What is the eye like if it's long sighted How do you correct long sightedness
The eyeball is too short or the lens is too thin. This means that distant objects are in focus, but near objects are focuses behind the retina
28
What does the focal length and power depend on
The curvature- a more curved lens has a higher power and shorter focal length The refractive index- a high refractive index has a higher power and shorter focal length
29
What is internal reflection
When a ray of light travels from glass into air, some light is reflected at the interface
30
When does total internal reflection occur
When the angle of incidence exceeds a certain value, called the critical angle
31
When is a total internal reflection used in medicine
With endoscopes for internal examinations, which removes the need for surgery to see inside the patients body. The optical fibre is used to provide illumination inside the body by shining a light through the fibre
32
What are the uses of lasers in medicine Examples of surgical procedures using lasers
Cutting Burning Cauterising Removing verrucas Delicate laser eye surgery
33
What is the momentum
The turning effect of a force
34
How do you increase the moment
Increase the force applied | Increase the perpendicular distance between the line of action of the force and the pivot
35
What is the centre of mass of an object
The point through which the whole worthy of the object is considered to act
36
How do you find the centre of mass
Hang the sheet and a plumb line from one point so both are free to rotate. Mark the position of the plumb line as a vertical line Hangs the sheet from a different position. Mark the position of the second plumb line The centre of mass is the point where the two lines cross.
37
Why would a car topple over
If the line of action of the weight of the car lies outside its base, the car will topple over
38
How can the stability of car be increased
Lower centre of mass | A wider base
39
Why can't liquids be compressed
The particles are close together
40
What happens when an object moves in a circle continuously
It accelerates towards the centre of the circle. This acceleration does not change the speed of the object, but the direction of its motion I.e. It's velocity The resultant force causing this acceleration is called the centripetal force
41
What 3 things can increase the centripetal force
The mass of the object increasing The speed of the object increasing The radius of the circle decreases
42
How is the size of the current increased (2)
Increases the size of the current | Increase the strength of the magnetic field
43
How is the direction of the force reversed (2)
Reverse the direction of flow of the current | Reverse the direction of the magnetic field
44
When is Flemings right hand rule used
To work out what direction the force induced will act
45
What does each finger and thumb show in Flemings left hand rule
The first finger points in the direction of the magnetic field The second finger points in the direction of the current flow The thumb will then be pointing in the direction of the force
46
What do transformers rely on to convert one voltage to another
Electromagnetic induction
47
How is a potential difference induced How will a current be induced
If a wire or a coil of wire cuts through the lines of force of a magnetic field If the wire is part of a complete circuit
48
How do you induce a current in one direction
Move the magnet into the coil
49
How can a current be induced in the opposite direction
By moving the magnet out of the coil | By moving the other pole of the magnet into the coil
50
Hal is the size of the induced potential difference increased
Increase the speed of movement of the magnet or the coil Increase the strength of the magnetic field Increase the number of turns on the coil
51
What does a transformer do What do transformers consist of
Changes the electrical energy from one potential difference to another potential difference Two coils called the primary and the secondary coils, wrapped around a soft iron core
52
How does the potential difference get from the primary coil to the secondary coil
An alternating potential difference across the primary coil will cause an alternating current to flow. This alternating current creates a continually changing magnetic field in the iron core, which induces an alternating potential difference across the secondary coil
53
What is a step up transformer like
There are more turns on the secondary coil than the primary coil so the potential difference is greater leaving the secondary coil than that of the primary coil
54
What is a step down transformer like
There are fewer turns on the secondary coil than the primary coil so the potential difference is lower leaving the secondary coil than that of the primary coil
55
What happens when the voltage increases
The current decreases
56
What are switch mode transformers
They are lighter and smaller than traditional transformers. They produce less heat and use very little power when no kid is applied. This makes them ideal for applications like mobile phone rechargers because their small size makes them more portable and once the phone is fully charged the transformer acts as a switch and so does not waste energy

Physics 2 And 3 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions