SI Units

Question 1

List the SI base units?

Answer 1

Seconds (Time)
Moles (Amount of Substance)
Meter (Length)
Ampere (Current)
Candela (Intensity of illumination)
Kelvin (Temperature)
Kilogram (Mass)

Question 2

What are the basic derived SI units for the following: area, volume, speed, velocity, acceleration and current density?

Answer 2

area=m2
volume=m3
speed=m/s
velocity=m/s with direction
acceleration=m/s2
current density= amp.m2

Question 3

Describe the following complex derived SI units: Newton, Pascal, Joule, Watt, Coulomb and Volt.

Answer 3

Newton N Force
kg⋅m/s2

Pascal Pa Pressure N/m2
kg/ms2

Joule J Energy N⋅m or C⋅V or W⋅s
kgm2/s2

Watt W Power J/s, V⋅A
kg⋅m2⋅s-3

Coulomb C Electrical charge
s⋅A

Volt V Voltage W/A, J/C
kg⋅m2⋅s-3⋅A-1

Question 4

What formula describes the relationship between watts, amps and voltage?

Answer 4

Voltage x Amps = Watts

Question 5

What is 0 degrees C in kelvin?

Answer 5

273.15 kelvin

Question 6

What is the equivalent pressure of 1atmosphere in: Pascal, KPa, Bar, cmH2O, mmHg, PSI (pound per square inch)

Answer 6

1 atmosphere = 1.013 bar = 101.3 KPa = 101300 Pascal = 1020cmH2O = 760mmHg = 14.5 PSI