Topic 1: Measurements and uncertainties Flashcards

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1
Q

What is the base unit for length?

A

metre

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2
Q

What is the symbol for metre?

A

m

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3
Q

What is the base quantity of a meter?

A

length

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4
Q

What is the base unit for mass?

A

kilogram

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5
Q

What is the symbol for a kilogram?

A

kg

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6
Q

What is the base quantity for a kilogram?

A

mass

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7
Q

What is the base unit for time?

A

second

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8
Q

What is the symbol for a second?

A

s

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9
Q

What is the base quantity for a second?

A

time

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10
Q

What is the base unit for a current?

A

ampere

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11
Q

What is the symbol for an ampere?

A

A

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12
Q

What is the base quantity for an ampere?

A

current

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13
Q

What is the base unit for temperature?

A

Kelvin

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14
Q

What is the symbol for Kelvin?

A

K

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15
Q

What is the base quantity for Kelvin?

A

temperature

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16
Q

What is the base unit of an amount of substance?

A

mole

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17
Q

What is the symbol for mole?

A

mol

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18
Q

What is the base quantity for a mole?

A

Amount of substance

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19
Q

What are derived units?

A

units that are made up out of base units

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20
Q

What are units that are made up out of base units?

A

derived units

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21
Q

What is the unit for force?

A

Newton

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22
Q

What does a Newton measure?

A

force

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23
Q

What is the unit for energy?

A

Joule

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24
Q

What does a Joule measure?

A

energy

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25
Q

What is the unit for pressure?

A

Pascal

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26
Q

What does a Pascal measure?

A

pressure

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27
Q

What is the unit for power?

A

Watt

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28
Q

What does a watt measure?

A

power

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29
Q

What is the unit for electric charge?

A

Coloumb

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30
Q

What does a Coulomb measure?

A

electric charge

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31
Q

What is the symbol for Newton?

A

N

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32
Q

What is the symbol for Pascal?

A

Pa

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33
Q

What is the symbol for Joule?

A

J

34
Q

What is the symbol for watt?

A

W

35
Q

How do you multiply scientific notation?

A

multiply numbers and add exponents

36
Q

How do you divide scientific notation?

A

divide numbers and subtract exponents

37
Q

What is precision?

A

how well repeated measurements of a value agree with one another (exact)

38
Q

What is how well repeated measurements of a value agree with one another (exact)?

A

precision

39
Q

What is accuracy?

A

how well a measurement agrees with the true value (correct)

40
Q

What is how well a measurement agrees with the true value (correct)?

A

accuracy

41
Q

What is calibration?

A

an instrument that is precise but not accurate can be calibrated

42
Q

What is an instrument that is precise but not accurate can be calibrated?

A

calibration

43
Q

When using an analog scale, what is the uncertainty?

A

plus or minus half the smallest scale division

44
Q

On what scale is it when the uncertainty is plus or minus half the smallest scale division?

A

analog scale

45
Q

When using a digital scale, what is the uncertainty?

A

plus or minus the smallest unit shown

46
Q

On what scale is it when the uncertainty is plus or minus the smallest unit shown?

A

digital scale

47
Q

When taking repeated measurement how do you find the uncertainty?

A

find the difference between the average and the measurement that is furthest from the average

48
Q

How do you find the order of magnitude?

A

Put things in 10’s and see how many you need (exponent) for estimation

49
Q

What is the order of magnitude for the size of subatomic particles to the extent of the visible universe?

A

10^-15 m to 10^25 m

50
Q

What is the order of magnitude for the mass of the electron to the mass of the universe?

A

10^-30 kg to 10^50 kg

51
Q

What is the order of magnitude for time for light to cross a nucleus to the age of the Universe?

A

10^-23 s to 10^18 s

52
Q

What is the order of magnitude for the size of a hydrogen atom?

A

10^-10 m

53
Q

What is the order of magnitude for the size of a proton?

A

10^-15 m

54
Q

What is the ratio of diameter of a hydrogen atom to its nucleus?

A

10^-10/10^-15 = 10^5

55
Q

What is displacement?

A

the distance moved in a stated direction (the distance and direction from the starting point)

56
Q

What is the distance moved in a stated direction (the distance and direction from the starting point)?

A

displacement

57
Q

Is displacement a vector?

A

Yes

58
Q

What is velocity?

A

the rate of change of displacement

59
Q

What is the rate of change of displacement?

A

velocity

60
Q

Is velocity a vector?

A

Yes

61
Q

What is acceleration?

A

the rate of change of velocity

62
Q

What is the rate of change of velocity?

A

acceleration

63
Q

Is acceleration a vector?

A

Yes

64
Q

What is average speed/velocity?

A

change in distance/displacement divided by time taken over a period of time

65
Q

What is the change in distance/displacement divided by time taken over a period of time?

A

average speed/velocity

66
Q

What is instantaneous speed/velocity?

A

the change in distance/displacement divided by time at one particular time

67
Q

What is the change in distance/displacement divided by time at one particular time?

A

instantaneous speed/velocity

68
Q

Is motion relative?

A

Yes

69
Q

What is a frame of reference?

A

a point from which a situation is observed

70
Q

What is a point from which a situation is observed?

A

a frame of reference

71
Q

What is a scalar quantity?

A

can be described by a number with units

72
Q

What is a vector quantity?

A

must be described by a number (its magnitude) and its direction

73
Q

How do you find displacement?

A

s2-s1

74
Q

What are systematic errors and examples of them?

A

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
Q

What are random errors and examples of them?

A

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
Q

What are absolute uncertainties?

A

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
Q

What are fractional uncertainties?

A

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
Q

What are percentage uncertainties?

A

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
Q

What is the combination of the uncertainties of different quantities called?

A

Propagation of uncertainties

80
Q

What do you do to the uncertainty of two values when you add or subtract them?

A

You add the absolute uncertainties.

81
Q

What do you do to the uncertainty of two values when you multiply or divide them?

A

You add their fractional or percentage uncertainties.