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Conductance and its Relation

Conductance:

The conductance of a material is its property which tells us with   how easily current can flow through that material. In simplest way it is defined as
“Reciprocal of resistance is called conductance.” It is denoted by G and is given by
                    G=1/R

Unit:

The unit of conductance is mho or siemen and is represented  Ʊ.

Relation:

As conductance is reciprocal of resistance so it is inversely proportional to the length of the conductor but directly proportional to the area. According to above statement

               G α 1/L ........(1)
               G α A ...........(2)
By combing above two relations we have 
            Gα A/L
or 
                 G= σ A/L
where  σ= Conductivity and is defined as

Conductivity:
The reciprocal of resistivity is called conductivity. It is represented by σ.
Unit:
The unit of conductivity is mho per meter(Ʊ/m) or siemen per meter.

 Alternatively                 

As we know that
                              R= (ρL)/A ....(1)
Also
                       R=1/G .......(2)

 By comparing (1) & (2), we get
                         1/G=(ρL)/A

 On simplifying 
                         G=1/ρ(A/L)
where 
                           1/ρ= σ=Conductivity.

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