Topic 1: Measurements and uncertainties Flashcards
1
Q
What is the base unit for length?
A
metre
2
Q
What is the symbol for metre?
A
m
3
Q
What is the base quantity of a meter?
A
length
4
Q
What is the base unit for mass?
A
kilogram
5
Q
What is the symbol for a kilogram?
A
kg
6
Q
What is the base quantity for a kilogram?
A
mass
7
Q
What is the base unit for time?
A
second
8
Q
What is the symbol for a second?
A
s
9
Q
What is the base quantity for a second?
A
time
10
Q
What is the base unit for a current?
A
ampere
11
Q
What is the symbol for an ampere?
A
A
12
Q
What is the base quantity for an ampere?
A
current
13
Q
What is the base unit for temperature?
A
Kelvin
14
Q
What is the symbol for Kelvin?
A
K
15
Q
What is the base quantity for Kelvin?
A
temperature
16
Q
What is the base unit of an amount of substance?
A
mole
17
Q
What is the symbol for mole?
A
mol
18
Q
What is the base quantity for a mole?
A
Amount of substance
19
Q
What are derived units?
A
units that are made up out of base units
20
Q
What are units that are made up out of base units?
A
derived units
21
Q
What is the unit for force?
A
Newton
22
Q
What does a Newton measure?
A
force
23
Q
What is the unit for energy?
A
Joule
24
Q
What does a Joule measure?
A
energy
25
What is the unit for pressure?
Pascal
26
What does a Pascal measure?
pressure
27
What is the unit for power?
Watt
28
What does a watt measure?
power
29
What is the unit for electric charge?
Coloumb
30
What does a Coulomb measure?
electric charge
31
What is the symbol for Newton?
N
32
What is the symbol for Pascal?
Pa
33
What is the symbol for Joule?
J
34
What is the symbol for watt?
W
35
How do you multiply scientific notation?
multiply numbers and add exponents
36
How do you divide scientific notation?
divide numbers and subtract exponents
37
What is precision?
how well repeated measurements of a value agree with one another (exact)
38
What is how well repeated measurements of a value agree with one another (exact)?
precision
39
What is accuracy?
how well a measurement agrees with the true value (correct)
40
What is how well a measurement agrees with the true value (correct)?
accuracy
41
What is calibration?
an instrument that is precise but not accurate can be calibrated
42
What is an instrument that is precise but not accurate can be calibrated?
calibration
43
When using an analog scale, what is the uncertainty?
plus or minus half the smallest scale division
44
On what scale is it when the uncertainty is plus or minus half the smallest scale division?
analog scale
45
When using a digital scale, what is the uncertainty?
plus or minus the smallest unit shown
46
On what scale is it when the uncertainty is plus or minus the smallest unit shown?
digital scale
47
When taking repeated measurement how do you find the uncertainty?
find the difference between the average and the measurement that is furthest from the average
48
How do you find the order of magnitude?
Put things in 10's and see how many you need (exponent) for estimation
49
What is the order of magnitude for the size of subatomic particles to the extent of the visible universe?
10^-15 m to 10^25 m
50
What is the order of magnitude for the mass of the electron to the mass of the universe?
10^-30 kg to 10^50 kg
51
What is the order of magnitude for time for light to cross a nucleus to the age of the Universe?
10^-23 s to 10^18 s
52
What is the order of magnitude for the size of a hydrogen atom?
10^-10 m
53
What is the order of magnitude for the size of a proton?
10^-15 m
54
What is the ratio of diameter of a hydrogen atom to its nucleus?
10^-10/10^-15 = 10^5
55
What is displacement?
the distance moved in a stated direction (the distance and direction from the starting point)
56
What is the distance moved in a stated direction (the distance and direction from the starting point)?
displacement
57
Is displacement a vector?
Yes
58
What is velocity?
the rate of change of displacement
59
What is the rate of change of displacement?
velocity
60
Is velocity a vector?
Yes
61
What is acceleration?
the rate of change of velocity
62
What is the rate of change of velocity?
acceleration
63
Is acceleration a vector?
Yes
64
What is average speed/velocity?
change in distance/displacement divided by time taken over a period of time
65
What is the change in distance/displacement divided by time taken over a period of time?
average speed/velocity
66
What is instantaneous speed/velocity?
the change in distance/displacement divided by time at one particular time
67
What is the change in distance/displacement divided by time at one particular time?
instantaneous speed/velocity
68
Is motion relative?
Yes
69
What is a frame of reference?
a point from which a situation is observed
70
What is a point from which a situation is observed?
a frame of reference
71
What is a scalar quantity?
can be described by a number with units
72
What is a vector quantity?
must be described by a number (its magnitude) and its direction
73
How do you find displacement?
s2-s1
74
What are systematic errors and examples of them?
Systematic errors are constant errors that are due to faults in the system used to measure a variable.
Examples are miscalibration, wearing down over time, or a constant delay in every reading.
They will be precise but not accurate.
75
What are random errors and examples of them?
Random errors can occur in any method of measuring but happen primarily when estimating.
These will differ from trial to trial and are not precise.
For example, measuring the speed of sound when making a loud clap a distance from the wall might cause a random error due to the reaction time of the experimenters measuring the time it takes the sound to travel.
76
What are absolute uncertainties?
When the uncertainty is given in the same unit as the answer given and should be written to the same number of decimal places.
E.g. 294.56 ± 3.01 N
77
What are fractional uncertainties?
When the uncertainty is given as a fraction of the original quantity. It is dimensionless (without units).
E.g. 2.6 ± 0.2 = 2.6 ± (0.2/2.6 or 0.077)
78
What are percentage uncertainties?
When the uncertainty is given as a percentage of the original quantity. You can get this from multiplying the fractional uncertainty by 100.
E.g. 2.6 ± 0.2 = 2.6 ± 7.7%
79
What is the combination of the uncertainties of different quantities called?
Propagation of uncertainties
80
What do you do to the uncertainty of two values when you add or subtract them?
You **add** the **absolute** uncertainties.
81
What do you do to the uncertainty of two values when you multiply or divide them?
You **add** their **fractional** or **percentage** uncertainties.
