List of Important SI Units of Measurement

In government exams like SSC, Banking, Railways, etc we find many questions from the General Science section. This is a very broad section and sometimes questions are very factual. In this article we will cover the Physics section comprehensively so that students can learn and get most of the questions correct from this section. In this article, we will discuss the list of Important SI Units of Measurement.

SI Units of Measurement: An Introduction

• From ancient times to the present, the acceptance, description, and practical application of units of measurement have played very  important role in human endeavors. Various unit systems have prevailed over the years. 
• The International System of Units or SI units is a globally agreed system of measurements that has been in place for more than two centuries.Lets understand it briefly.
  

Different Systems of Measurement :

• Unit systems tend to differ from country to country. Various unit types, which we are commonly  using  today include the FPS, CGS, SI, and MKS units. The main measurement systems in use today are the imperial system, the metric system, and the natural system. Let’s take a quick look at these different systems.
  
• Imperial System: Imperial units, also known as the British Imperial system, is a standard or standard system of weights and measures. It was officially used in England from 1824 until the introduction of the metric system in 1965.
  
• Metric System: The metric system is the modern international system of units and the international standard system. This system is called SI. Standardization is one of the key aspects of modern systems. Each unit has a known size. 
  
• Natural Systems: Natural units are physical units of measurement based solely on common physical constants. The elementary charge “e” is the natural unit of electric charge and the speed of light “c” is the natural unit of velocity.

Application of Units of Measurement:

• In everyday life, people use units of measurement so often that they give little thought to what they are doing. A driver goes to a petrol station and pumps 5 liters (volumetric) of petrol into the engine. Motorists use another unit of measurement, the rupee, in the form of banknotes, debit or credit cards, to pay for petrol more economically than scientifically.
  
• The failure of NASA’s Mars Climate Orbiter, which was accidentally destroyed instead of going into orbit during a trip to Mars in September 1999, due to misunderstandings about the value of power.  This is an example showing Different computer programs used different units of measurement. A lot of effort, time, and money is wasted.
  
• A chemist or scientist needs standardized measurements because for an experiment to be useful it must be possible to repeat it. Experimental results are useless unless a chemist knows exactly how much one element is mixed with another to form a particular compound.
  
• When Columbus prepared for his transatlantic voyage in the 1480s, Columbus noted that in the degree scale mentioned in Arabic calculations he was 56⅔ miles, but in Italy, he was much shorter.  I mistakenly believed it to be identical to a mile of 1,480 meters. As a result, his planetary power and circumference calculations were about 25% too small.

List of Important SI Units of Measurement:

Quantity	SI Unit	Symbol
Length	meter	m
Mass	kilogram	kg
Time	second	s
Work and Energy	Joule	J
Electric current	ampere	A
Temperature	kelvin	K
Intensity of flame	candela	cd
Angle	radian	rad
Solid angle	steradian	sr
Force	newton	N
Area	square meter	m2
Volume	cubic meter	m3
Speed	meter/second	ms-1
Angular Velocity	radian/second	rad s-1
Frequency	Hertz	Hz
Moment of inertia	kilogram square meter	kg m2
Momentum	kilogram meter per second	kg m s-1
impulse	newton second	Ns
Angular Momentum	kilogram square meter per second	kgm2s-1
Pressure	pascal	Pa
Power	watt	W
Surface tension	newton per meter	Nm-1
Viscosity	newton second per square meter	N. s. m-2
Thermal Conductivity	watt per meter per degree celsius	Wm-1C-1
Specific Heat capacity	joule/kilogram/kelvin	Jkg-1K-1
Electric charge	coulomb	C
Potential Difference	volt	V
Electric Capacity	farad	F
Magnetic Induction	henry	H
Magnetic Flux	weber	Wb
Luminous Flux or Photometric power	lumen	lm
Intensity of Illumination	lux	lx
Wavelength	Angstrom	Å
Astronomical Distance	light year	ly
Electric Resistance	ohm	Ω