Measurement Flashcards

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1
Q

What are the base quantities tested in the syllabus?

A

Mass
time
length
electric current
thermodynamic temperature
amount of substance

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2
Q

Name and symbol of SI Base Quantity:Mass

A

kilogram,kg

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3
Q

Name and symbol of SI Base Quantity:Time

A

second,s

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4
Q

Name and symbol of SI Base Quantity:Length

A

metre,m

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5
Q

Name and symbol of SI Base Quantity:Electric current

A

ampere,A

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6
Q

Name and symbol of SI Base Quantity:Thermodynamic Temperature

A

kelvin,K

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7
Q

Name and symbol of SI Base Quantity:Amount of substance

A

mole,mol

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8
Q

What is the molar mass of carbon-12?

A

12 grams

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9
Q

How many atoms of carbon does carbon-12 have?

A

6.02 x 10^23

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10
Q

Name the derived unit and how it is expressed in base units for the physical quantity: Area

A

m^2,m^2

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11
Q

Name the derived unit and how it is expressed in base units for the physical quantity: Force

A

N, kg m s^-2

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12
Q

Name the derived unit and how it is expressed in base units for the physical quantity: Energy

A

J, kg m^2 s^-2

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13
Q

Express the unit for charge Q in terms of the SI base units.

A

A s

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14
Q

What does a physical equation being homogenous mean?

A

It means that all terms of the equation must have the same SI bas eunits.

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15
Q

What is a dimensionless quantity?

A

A dimensionless quantity is a quantity with no unit.

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16
Q

What is a derived unit?

A

A derived unit is a unit expressed in terms of the product and/or quotient of base units.

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17
Q

Explain why the unit of energy, joules, is said to be a derived unit.

A

A derived unit is a unit expressed in terms of the product and/or quotient of base units. The unit of energy, joule is said to be a derived unit because it can be expressed in terms of the product and/or quotient of the base units: kilogram,metre and second.

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18
Q

Determine the base units of density p and pressure p.

A

Density: kg m^-3
Pressure: kg m^-1 s^-2

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19
Q

Considering the unit of c is m s^-1 and that c is a gas,suggest what quantity may be represented by the symbol c.

A

Since the base units of c is m s^-1, the symbol c may be representing the mean speed of gas molecules

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20
Q

Tell the power and abbreviation of the prefix: deci

A

10^-1,d

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21
Q

Tell the power and abbreviation of the prefix: centi

A

10^-2,c

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22
Q

Tell the power and abbreviation of the prefix: milli

A

10^-3,m

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23
Q

Tell the power and abbreviation of the prefix: micro

A

10^-6, µ

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24
Q

Tell the power and abbreviation of the prefix: nano

A

10^-9,n

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25
Q

Tell the power and abbreviation of the prefix: pico

A

10^-12,p

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26
Q

Tell the power and abbreviation of the prefix: femto

A

10^-15,f

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27
Q

Tell the power and abbreviation of the prefix: kilo

A

10^3,k

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28
Q

Tell the power and abbreviation of the prefix: mega

A

10^6,M

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29
Q

Tell the power and abbreviation of the prefix: giga

A

10^9,G

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30
Q

Tell the power and abbreviation of the prefix: tera

A

10^12,T

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31
Q

Tell the power and abbreviation of the prefix: peta

A

10^15,P

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32
Q

Leave your answers in their basic units and in standard form: Calculate the speed of an electron that travels 50nm in 12µs.

A

4.2 x 10^-3 m s^-1

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33
Q

Leave your answers in their basic units and in standard form: Calculate the current flowing through a 2.0MΩ resistance with a potential difference of 9.0kV across it.

A

4.5 x 10^-3 A

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34
Q

Convert 80 cm^2 to m^2.

A

8.0 x 10^-3 m^2

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35
Q

Convert 6.0 x 10^-4 m^3 to cm^3.

A

6.0 x 10^2 cm^3

36
Q

Convert 16 m s^-1 to km h^-1.

A

57.6 km h^-1

37
Q

Convert 13.6 g cm^-3 to kg m^-3

A

13600 kg m^-3

38
Q

What is the order of magnitude of this quantity: Diameter of atom

A

10^-10 m

39
Q

What is the order of magnitude of this quantity: Diameter of nucleus

A

10^-15 m

40
Q

What is the order of magnitude of this quantity: Wavelength of visible light(Violet to red)

A

10^-7 m

41
Q

What is the order of magnitude of this quantity: Density of water

A

10^3 kg m^-3

42
Q

What is the order of magnitude of this quantity: Average speed of a runner

A

1 m s^-1 or 10 km h^-1

43
Q

What is the order of magnitude of this quantity: Car speed on an expressway

A

10 m s^-1,100 km h^-1

44
Q

What is the order of magnitude of this quantity: Power on a light bulb

A

10 W

45
Q

What is the order of magnitude of this quantity: Average electrical power of an iron/air-con

A

10^3 W

46
Q

What is the order of magnitude of this quantity: Mass of an average person

A

10^2 kg

47
Q

What is the order of magnitude of this quantity: Mass of a car

A

10^3 kg

48
Q

What is the order of magnitude of this quantity: Mass of unladen lorry

A

10^3 kg

49
Q

What is the order of magnitude of this quantity: Mass of Earth

A

10^25 kg

50
Q

What is the order of magnitude of this quantity: Mass of Sun

A

10^30 kg

51
Q

Definition of random errors

A

Random errors are errors of measurements in which the measured quantities deviate from the mean value with varying magnitudes and different signs.

52
Q

Definition of systematic errors

A

Systematic errors are errors of measurements in which the measured quantities deviate from the true value by a fixed magnitude and constant sign.

53
Q

How can you reduce systematic erros?

A

Systematic errors can be eliminated to obtain the true value of a measured quantity.

54
Q

How can you reduce random errors?

A

Random errors can only be minimized(But not eliminated) through various approaches.

55
Q

An experiment is set up as shown to determine the spring constant of a spring. Using the formula mg=kx, the spring constant k may be determined by finding the extension of the spring,x, and the mass of the load applied,m. Give 1 example of a systematic error and a random error which could occur in this expermient.

A

Random:
1)Reading from the metre rule taken when the spring system is not stable
2)Parallax error arising from measurement using the metre rule because there is a gap between load and metre rule
Systematic:
1)The ruler may not be vertical.
2)Wrong calibration of electronic mass balance

56
Q

For each of the following imporvements, state whether it reduces random or systematic error: Take timings for a large number of oscillations(so that the timing exceeds 20 s) to find the period of oscillation

A

Random error

56
Q

For each of the following improvements, state whether it reduces random or systematic error: Adjust the instrument to remove its zero error before measurement

A

Systematic error

57
Q

For each of the following improvements, state whether it reduces random or systematic error: Measure the diameter of a wire at different positions and calculate its average value.

A

Random error

58
Q

For each of the following improvements, state whether it reduces random or systematic error: Determine the zero error in the instrument and account for it by substracting from the measured value

A

Systematic error

59
Q

For each of the following improvements, state whether it reduces random or systematic error: Place the pointer of instrument as close to the scale as possible to minimize parallax error.

A

Random error

60
Q

For each of the following improvements, state whether it reduces random or systematic error: Use aids such as a plane mirror or a set square when reading a scale to minimze parallax error.

A

Random error

61
Q

For each of the following improvements, state whether it reduces random or systematic error: Drawing a graph of best fit from data points collected from the experiment.

A

Random error

62
Q

Definition of accuracy

A

Accuracy is a measure of how close the average of the emasured values is to the true value.

63
Q

Definition of precision

A

Precision is a measure of how close each measured value agrees with one another.

64
Q

With high accuracy, it reduces what errors?

A

Systematic errors

65
Q

With high precision, it reduces what errors?

A

Random errors

66
Q

Precision of analogue watch and digital watch

A

Analogue:+-0.01s
Digital:+-1s

67
Q

How do you determine the mean of 5 values?

A

Average them

68
Q

How do you determine the spread of 5 values?

A

Max value - Min value

69
Q

Uncertainty in measurement of instrument: Metre rule

A

1mm

70
Q

Uncertainty in measurement of instrument: Vernier calipers

A

0.1mm

71
Q

Uncertainty in measurement of instrument: Micrometer screw gauge

A

0.01mm

72
Q

Uncertainty in measurement of instrument: Digital stopwatch

A

0.01s

73
Q

Uncertainty in measurement of instrument: Thermometer

A

0.5 degrees

74
Q

Does the actual uncertainty carry a unit?

A

Yes

75
Q

Does the fractional uncertainty carry a unit?

A

No

76
Q

Does the percentage uncertainty carry a unit?

A

No

77
Q

Actual uncertainty is expressed in _ sf

A

1

77
Q

Fractional uncertainty is expressed in _ sf

A

2

78
Q

Why do we have to calculate fractional and percentage uncertainty?

A

For smaller objects, there is a higher percentage uncertainty.

78
Q

Percentage uncertainty is expressed in _ sf

A

2

79
Q

When you have your value with an uncertainty, what should you consider on the decimal places?

A

The decimal places must be the same and must have 1sf for uncertainty.

80
Q

What is the actual uncertainty of a derived quantity for addition and/or subtraction operation?

A

The summation of the actual uncertainties of the individual quantities

81
Q
A
82
Q
A