As Flashcards
(71 cards)
1
Q
Tera T
A
10^12
2
Q
Giga G
A
10^9
3
Q
Mega M
A
10^6
4
Q
Kilo K
A
10^3
5
Q
Milli m
A
10^-3
6
Q
Micro.
A
10^-6
7
Q
Nano n
A
10^-9
8
Q
Pico. P
A
10^-12
9
Q
Femto. f
A
10^-15
10
Q
Base units (X7)
A
Metres Seconds Kilogram Amps Kelvin Moles Candela
11
Q
Linear relationship
A
2 variables are directly proportional
12
Q
Limit of proportionality
A
Point where variables are no longer proportional
13
Q
Elastic limit
A
The last point where if the force is released the object will return to its original shape
14
Q
Yield point
A
Where small increase in force creates large extension
15
Q
Tough
A
Absorbs energy by deforming plastically h
16
Q
Hard
A
Not readily scratched or dented
17
Q
Stiff
A
Large force = small deformation
18
Q
Strong
A
Not ductile. High breaking stress
19
Q
Smooth
A
Low friction surface
20
Q
Durable
A
Properties don’t worsen with repeated loading and unloading
21
Q
Malleable
A
Large plastic deformation for small stress
22
Q
Brittle
A
Strong as little strain for high stress. Doesn’t stretch. Breaks suddenly
23
Q
Plastic
A
Very small elastic region
24
Q
Plastic deformation
A
Material permanently stretched
25
Elastic deformation
Material returns to original shape and size
26
Work done is the area
Under a force displacement graph
27
Impulse is the area
Under a force time graph
28
Elastic collision
Momentum and kinetic energy conserved
29
Inelastic collision
Momentum is conserved but kinetic energy is converted to other forms
30
Definition moment
Force x perpendicular distance from pivot
31
Principle of moments
At equilibrium the sum of clockwise moments must equal the sum of anti clockwise moments
32
A couple is
A pair of forces of equal size which act parallel to each other but in opposite directions
33
Moment in a couple
Size of 1 force x perpendicular distance between lines of action of the forces
34
In a displacement time graph gradient=
Velocity
35
To find the instantaneous velocity at a certain point in a displacement time graph
Draw a tangent to the curve
36
Advantages of using data loggers to draw velocity time graphs
(3)
Data is more accurate
Higher sampling rates
Displayed in real time
37
SUVAT equations
| 5
```
V=U +at
V^2=U^2+2as
S=Ut+0.5at^2
S=Vt-0.5at^2
S=0.5(U+V) X t
```
38
Free fall
The motion of an object undergoing an acceleration of g
39
Newtons 1st law
An object will move st constant speed unless there is a resultant force acting on it
40
Newtons 2nd law
Acceleration is proportional to rate
F=ma
41
Newtons 3rd law
If object A exerts a force in object B then object B will exert an equal but opposite force in object A
42
Mechanical waves
Can be transverse or longitudinal
They need a medium to travel through
43
Electromagnetic waves
Always transverse. Can travel through a vacuum
44
Transverse waves
Particles oscillate perpendicular to the direction of energy transfer
Can be polarised
45
Longitudinal waves
Particles oscillate parallel to the direction of energy transfer
46
Polarising filters
Only allow through oscillations in 1 plane
47
Light can be partially polarised when
They are reflected from some surfaces
48
Uses of polarising filters
Sunglasses
3D glasses
Privacy screens
Identify substances ( doesn't use up the substance)
49
Coherent
Same wavelength and frequency
Fixed phases difference
50
Path difference
How much further one wave has traveled than another
51
Diffraction
Spreading out of waves as they pass through a gap or go round an obstacle
52
Monochromatic
All the same wavelength and frequency
53
Increasing slit width
Narrower central maximum and higher intensity
54
Increasing wavelength
More diffraction. Wider central maximum and lower intensity
55
Young double slit provided evidence that light is a
Wave because only waves diffract and interfere
56
Spectra can be used to identify
And I'm
Elements
X-ray crystallography
57
One way to reduce pulse broadening is to decrease
The core diameter
Less path difference possible
But the signal is weaker
58
One way to reduce pulse broadening is to have
Index grading
n changed. Smaller n = faster light so waves get out at same time
But it is very expensive
59
Dispersion and absorption cause
Signal degradation
60
Absorption in optical fibres
Some energy is absorbed by the material the fibre is made of
So it reduces the amplitude
61
Dispersion in an optical fibre
Modal dispersion= light rays enter at different Angles so take different paths
Material dispersion = light consists of different wavelengths which travel at different speeds in the fibre .using monochromatic light stops this
62
Dispersion causes
Pulse broadening
63
Evidence got the strong nuclear force
Electrostatic repulsion is a lot bigger than gravitational attraction
64
The anti electron neutrino is
A neutral Particle with virtually not mass which carries away some energy and momentum
65
Electromagnetic force
Charge particles
| Photons
66
Strong force
Hadrons
| Gluons
67
Weak force
Hadrons + leptons
| Bosons
68
Weak interaction
Decay happens
Quark makeup of the hadron changes
Strangeness not always conserved
69
Work function
The amount of work done needed to liberate an electron
70
Stopping voltage
Amount of voltage needed to stop the flow of electrons
71
Wave particle duality evidence
Diffraction = light as a wave
Photoelectric effect =light as a particle
