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# Prefixes used in Physics

Table of prefixes

There is a small table of prefixes given in the book but there are some points which are normally not noticed by the students.

On the basis of exponent of ten the prefixes can be divided into two categories.
i) having a positive exponent
ii) having a negative exponent

the prefixes whose symbol is a capital alphabet are all those which have the exponent of 10 as a positive number.
e.g.
symbol of giga is G, symbol of mega is M.

On the other hand the small alphabets are used as symbol for positive as well as negative exponents.

e.g kilo(10^3) is denoted by k, nano (10^-9) has the symbol n and so on.

So what type of questions can be asked from this table?

1) You can be given a name of the prefix or symbol and can be asked which value does it represent or vice versa

2) You can be given a name of the prefix and can be asked about its symbol and vice versa

3) You can be asked questions like:

Capital alphabets are used as symbol for which type of prefixes
a) With exponents
b) With negative exponents
c) Both
d) none

Same question can be asked for small alphabets.

The above question can also be asked in the converse manner
i.e.
Positive exponents are used for prefixes whose symbols are
a) capital alphabets
b) small alphabets
c) both
d) none

4) You can be asked how much time one prefix is the other
e.g.
How many kilos make one tera?

Order of Magnitude:

The order of magnitude of a number is the power of ten when the number is expressed in scientific notation.
For example, if F = 5 x 10^7 and G= 9 x 10^6, then the order of magnitude of F is 7 and B is 6.

This term can be used in the tests, although not mentioned in the text books but should be known.