Various Principal Quantity in Physics

Various fundamental quantities in physics – Physics is a natural science that studies matter, its motion and behavior in space and time with related concepts such as energy and force. As one of the most fundamental sciences, the main goal of physics is to understand how the universe works. People or scientists who are experts in physics are called physicists or physicists.

Physics is one of the oldest scientific disciplines, perhaps the oldest also including astronomy. For more than two millennia, physics has been part of the natural sciences along with chemistry, biology and, to a lesser extent, branches of mathematics, but when the scientific revolution broke out in the 17th century, natural sciences had developed as a well-rounded program of study.

Physics was developed alongside many other disciplines, such as biophysics and quantum chemistry, and its physical boundaries are not clearly defined. New physics is sometimes used to explain the mechanisms underlying other sciences and pave the way for other fields of study such as mathematics and philosophy.

Physics also makes an important contribution to the development of technology that develops from theoretical thinking. For example, a broad understanding of electromagnetism and nuclear physics has directly led to the development of new products that have dramatically shaped modern society, such as televisions, computers, household appliances, and nuclear weapons. Advances in thermodynamics, industrialization, and advances in mechanics have influenced the development of computing.

In developing a product, of course, a unit value is needed to measure it. For that physics also acts as a science to calculate a fundamental quantity. The base quantity is a unit value. Therefore, on this occasion Sinaumedia will discuss basic quantities in physics. To find out more about the principal amount, let’s look at the following review.

Definition of Principal Amount

Magnitude is anything that has size, calculation, value, and unit of measure. The value increases the object’s properties. This property is displayed as a number after the measurement result. Since one quantity is different from another, a unit of measure is assigned to each quantity. Units also indicate that each quantity is measured differently.

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On the other hand, fundamental quantities are quantities with a single value that physicists agree on. Children in junior high and high school will receive these materials. More precisely, in physics.

The most common base quantities are length (m), mass (kg), time (s), temperature (K), current (A), luminous intensity (cd), and the amount of substance (mol). Fundamental quantities, among other things, have special properties, are taken directly from measurements, have units (not many units), and are predetermined.

Various Principal Amounts

Based on the International Unit (SI) system, there are 7 basic quantities that have been agreed upon. Here are the various principal quantities.


Length is used to measure the length of an object. In the International System of Units, the unit used for this quantity is the meter (m) and has dimensions (L). The tools used to measure length are then a ruler or ruler, measuring tape or tape measure, and vernier calipers.

In 1960, scientists determined that the meter is 1,650,763.73 times the wavelength of the orange-red radiation emitted by 86 krypton atoms in a vacuum. In 1983, the meter was redefined as the length of the path traveled by light in a vacuum during an interval of 1/299,792,458 second.


Mass is the amount of matter contained in an object. In SI, the unit of mass is the kilogram (kg). The kilogram is the mass of a metal cylinder made of platinum-iridium alloy kept at The International Bureau Of Weighs and Measures in Paris. The kilogram is the only non-transferable standard unit. Mass measuring tools include:

  • Arm Balance, which includes two or three arms.
  • Chemical balance, usually used to measure small masses.
  • Electronic/digital balance.


Time was originally defined as 1/86,400 hour day based on the Earth’s rotation on its axis. In SI, the unit of time is the second. In order to measure more accurate time, nowadays people prefer to use atomic clocks. These clocks are governed by the motion of certain atoms such as cesium, where 1 second corresponds to 9,192,631,770 vibrational periods of a cesium atom. Tools that can be used to measure units of time are clocks, hourglasses, sundials, watches, and stopwatches .


Temperature is a measure of the high and low temperature of an object. The SI unit for temperature is the Kelvin (K). The definition of temperature is based on the phase diagram of water or the location of the triple point of water (the temperature where the three phases of water coexist) is defined as 273.16 Kelvin. Absolute zero is defined as 0 Kelvin, so 1 Kelvin is defined as 1/273.16 times the temperature of water. An instrument that accurately measures the temperature of an object and expresses it numerically is called a thermometer.

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Strong currents

Current strength is the basic quantity used to determine the amount of current flowing from one place to another. The unit used for this current is Ampere (A). This is to maintain the amperage value generated. The magnitude of this current is indicated by the letter “I”. The tool that can be used to measure current strength is an ammeter.

Substance Amount

The next base quantity is the amount of substance. This amount of substance is used to calculate the number of particles in an object. The amount of this substance allowed in the SI system must use units of measurement in the form of moles. So the dimensions are N-shaped.

Light intensity

The last principal quantity is the intensity of light. It is used to measure whether light hits the surface of an object or not. The unit commonly used to determine the intensity of light is the candela (cd). In this case, the dimension used is J. On the other hand, you can also measure the light intensity using a tool called LuxMeter or LightMeter .

You, that’s the article about the various base quantities. Maybe you already know some measuring tools and units. However, this article provides an explanation of what is behind the units of measurement that we have used so far, namely the basic quantities that have been determined by physicists.