Logarithm

 

A logarithm is the power to which a base number must be raised to equal a given number.A system of numbers used in measuring exposure , density , sound level, etc (1985).

For everyday practical purposes the base is 10, giving what are called “common logarithms” ; 10 is the first power of 10 and is written as 10 1 . Thus for example;

10=10 1 and the logarithm of 10 is 1.0
100=10 2 and the logarithm of 100 is 2.0
1000=10 3 and the logarithm of 1000 is 3.0