SI Units Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

SI unit for time

A

Seconds

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

SI Unit for length

A

Meters

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

SI. unit for amount of substance

A

Moles

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

SI. unit For electric current

A

Amperes

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

SI. unit For luminous intensity

A

Candela

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

SI. unit For temperature

A

Kelvin

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

SI. unit For mass

A

Kilograms

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

How many base SI units are there?

A

7 (SMMACKK)

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

Origin of a second

A

Duration of time for caesium-133 atom to oscillate a certain number of times (9,192,631,770) I.e. it’s based on the frequency of radiation emitted from caesium-133

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

Origin of a metre

A

Length that light travels in a vacuum in 1/300,000,000 of a second

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

Origin of a mole (SI unit)

A

Amount of substance which contains as many elementary particles as there are atoms in 0.012kg (12g) of carbon-12

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

Origin of ampere (SI unit)

A

An ampere is the current which produces a force of 2x10^-7 newtons per metre between 2 parallel conductors 1metre apart in a vacuum

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

Origin of Candela (SI unit)

A

The luminous intensity of a perfect black body at a specified high temperature
I.e. monochromatic light

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

Origin of kelvin (SI unit)

A

1/273.16 of the thermodynamic triple point of water

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

What is the triple point of water

A

The point at which water, water vapour and ice all exist in equilibrium (relevant to kelvin definition)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Origin of kilogram (SI unit)

A

The mass of the prototype kilogram held in sevres France

*NOTE- the only base SI unit based on physical quantity . Others based on physical properties of defined systems which are reproducible over time. Risk of prototype degrading

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

How many derived electrical units are there?

A

4

(Volt, ohm, coulomb, farad)

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

What are the 4 electrical derived units

A

Volt, ohm, coulomb, farad

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

Define volt

A

Derived electrical unit of electrical potential. One volt is the difference of electrical potential between two points of a conductor carrying constant current of 1 ampere, when the power dissipated between these points is 1 watt

Watt = volt x ampere
Volt = watt/ampere

SI base units as 1 V = 1 kg m2 s-3 A -1 (one-kilogram meter squared per second cubed per ampere).

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

Define Ohm

A
  • Derived electric unit
  • unit of electrical resistance
  • if a potential of 1 volt is applied across a conductor and produces a current of 1 ampere, the resistance of this conductor is 1 ohm
    V=IR, R=V/I (Ohms Law)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Define coulomb

A
  • derived electrical unit
  • unit of charge or quantity of electricity
  • 1 coulomb is the quantity of electricity transported in 1 second by a current of 1 ampere

Coulomb = ampere x time

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

Define Farad

A
  • derived electrical unit
  • unit of capacitance
  • a capacitor has 1 farad of capacitance if a potential difference of 1 volt is present across its plates, when a charge of 1 coulomb is held by them

Q=CV

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is Volt a unit of?

A

Electrical potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is Ohm a unit of?

A

Electrical resistance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is coulomb a measure of?

A

Charge or quantity of electricity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is Farad a unit of?

A

Capacitance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How many derived non-electrical units are there

A

7
(Hertz, newton, pascal, joule, electronvolt, watt, Celsius)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is Hertz a unit of?

A

Frequency
- one hertz is a frequency of one cycle per second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is measured in Newtons?

A

Force

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Define Newton

A
  • derived non-electrical unit
  • force
  • 1 newton = the force which gives a mass of 1 kg the acceleration of 1 meter per second per second

1kg.m/s^2

32
Q

What is measured in Pascals?

A

Pressure

33
Q

Define Pascal

A
  • derived non-electrical unit
  • a pascal is the pressure of 1 newton per square
    Metre

1 kilogram per metre second squared (1kg/ms2)

or

1 newton per metre squared (1N/m2)

34
Q

What is measured in joules

A

Energy or work

35
Q

Define 1 joule

A
  • Derived non electrical unit
  • unit of energy or work
    -amount of work done when a force of one newton displaces a mass through a distance of one metre in the direction of that force.

1J=1N.m
1J= kg.m^2.s^-2

36
Q
A
37
Q

What is measured in electronvolt

A

ElectroMagnetic radiation

38
Q

Define electronvolt

A
  • derived non electrical unit
  • an electron volt is the energy required to move one electron through a potential difference of 1 volt in a vacuum and equals 1.6x10^-19 joules
39
Q

What is measured in watts?

A

Power

40
Q

Define Watt

A
  • derived non electrical unit
  • unit of power
  • power is the rate of energy expenditure so 1 watt = 1 joule per second
41
Q

What is measure in celsius

A

Temperature

42
Q

Define celsius

A
  • derived non electrical unit
  • unit of temperature
  • the size of 1 degree Celsius = 1 degree kelvin
  • the relationship is 1 Celsius = minus 273.15 Kelvin
43
Q

What is 1 Celsius in Kelvin?

A

Minus 273.15

44
Q

What is 1 kilopascal in mmHg?

A

7.5mmHg

45
Q

What is 1 kilopascal in cmH2O?

A

10.2cmH2O

46
Q

What is 1cmH20 in pascals?

A

98 pascals

47
Q

What is 1 atmosphere in kilopascals

A

101.325 KPa

48
Q

How many joules is 1 calorie equal to?

A

4.18

49
Q

How many newtons does 1kg weight equal?

A

9.81 newtons

50
Q

What prefix denotes 10^-12 of a unit?

A

Pico-

51
Q

What prefix denotes 10^-9 of a unit?

A

Nano-

52
Q

What prefix denotes 10^-6 of a unit?

A

Micro-

53
Q

What prefix denotes 10^-3 of a unit?

A

Milli-

54
Q

What prefix denotes 10^6 of a unit?

A

Mega

54
Q

What prefix denotes 10^3 of a unit?

A

Kilo

55
Q

What prefix denotes 10^9 of a unit?

A

Giga

56
Q

When expressed in SI units what is standard temperature and pressure

A

273.15 kelvin (equivalent 0 Celsius) and 101.325 kPa (equivalent 1 bar, 1 atmosphere and 750mmHg)

57
Q

What is avogadros hypothesis?

A
  • States that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.
  • the molecular weights of gases may be different but avogadros hypothesis states the number of molecules will be the same therefore more useful to express quantity if gas in terms of molecules - which is mole
58
Q

What is avogadros number?

A

-The number of particles there are in 0.012kg of carbon-12 and therefore the number of particles in a mole
- the number is 6.022x10^23

59
Q

What is the volume occupied by 1 mole of gas at standard temp and pressure?

A
  • 22.4L
  • one mole of any gas will occupy the same volume at the same temp and pressure (avogadros hypothesis)
60
Q
A
61
Q

In thermodynamics what is the triple point of a substance?

A

The temperature and pressure at which the 3 phases of that substance co-exist in thermodynamic equilibrium

62
Q

What is the triple point of water?

A

273.16 kelvin (0.01 Celsius)
611.73 pascals

63
Q

Denote Newtons in base units

A

Kg/m/s^2
(Newtons are product of mass (kg), multiplied with acceleration (meters per second per second squared))

64
Q

Denote Joules in SI units (base)

A

Joules = force x distance
Force = newton (expressed as kg.m.s^-2

Therefore Joules is simplified to kgm^2/s^2

65
Q

What is the SI unit for pressure?

A

Pascal

66
Q

1 atmosphere = how many bar?

A

1 bar

67
Q

Convert 1 bar to kPa?

A

1 bar = 101.3 kPa

68
Q

Convert 1 bar to kPa?

A

1 bar = 101.3 kPa

69
Q

Convert 1 atmosphere to mmHg

A

1 atm = 760 mmHg

70
Q

Convert 1 atm to cm H2O

A

1 atm = 1020 cmH2O

71
Q

Convert 1 atm to cm H2O

A

1 atm = 1020 cmH2O

72
Q

Convert 1 atm to PSI

A

1 atm = 14.69 PSI

73
Q

What is SI unit for magnetic flux?

A

Weber (Wb)

74
Q

What is SI unit for magnetic flux?

A

Weber (Wb)

75
Q

What is SI unit for magnetic flux density?

A

Tesla (T)
1 T = 1Wb/m2