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What are Prefixes in Physics

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what are prefix in physics


In this article, I will explain what are prefixes in physics and mention all the prefixes available in physics.

What is a Prefix in Physics? 

A prefix in physics simply refers to the addition of a letter or symbol to an s.i unit or physical quantity in order to shorten its figures for better understanding. 

Additionally, a prefix is always added before the unit and after the figures. 

Therefore, for an answer to be considered a prefix, it must contain a large figure that might look inappropriate to fit in as the final answer or into your calculation (because it will look cumbersome).

For Example, 0.00000789 may look inappropriate in a calculation. 

Instead, it’s converted into a standard form or to the power of 10. 

For example, 7.89 x 10-6

It is important to know that the power of 10 may turn out to be negative or positive depending on what you are dealing with.

Therefore, after writing 7.89 x 10-6 we will need to still shorten the figures by adding a prefix. 

Assuming it’s in Faraday, we can then write it as 

7.89 x 10-6 F

Hence, to add a prefix, we now say that 10-6 = micro = μ 

Thus, we can now replace 10-6 as micro = μ, by adding our prefix before our unit

Which implies, 7.89 μF = 7.89 micro faraday

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Refractive Index: How to Calculate an Apparent Displacement

Table of Prefixes: What are Prefixes in Physics

Here is a table to guide you on prefixes in physics

PrefixStandard formCurrent symbol
A table of prefixes in physics

History of Prefixes

We have 20 sets of prefixes that are accepted and being used for measurement globally. 

We started applying this form of the metric system after an agreement was reached in 1960.

In 2022, a British meteorologist (Richard J. C. Brown) came up with the idea of four more additional prefixes, and they are quetta, ronna, ronto, and quecto. These prefixes were added to the list of the existing prefixes we already have. 

Also, ronna and quetta are mostly used in data science. Additional prefixes are ronto (10-27) and quecto (10-30).

You also need to understand that joining two prefixes at the same time is not approved in science.

For example, writing HECTOMEGAGRAM does not make sense and should be avoided. 

In 1975, France was measuring units by applying Greek terms like myriad (10,000), double (2), and demi (½)

How to Write Prefixes in Physics 

Here is how to write prefixes in physics:

  • Write the figures you have obtained or given. For example, 20,000
  • Find the symbol of the prefix. For example c is for centi. Centi represent ten to the power of minus two (2).
  • The symbol of the unit you are calculating. For example, a meter is the unit of length. 
  • Add the three together. The figure comes first, followed by the prefix, and then the unit. For example, 200cm where 20,000(1/100)m.


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