Question

On what factor the resistance of conductor depends give its mathematical expression.Calculate The resistivity of a metal of length 2m at 20°C having the resistance of 20W and diameter 0.3mm?

Answer 1

Resistance of a cunductor depends upon its:
● Length :
Length of the cunductor is directly proportional to the resistance offered by the cunductor.
i.e. R∝l
● Area of cross section :
Area of cross section of the cunductor is inversly proportional to the resistance of the cunductor.
i.e. R ∝ 1/A
●Nature of its material:
Resistance offered by cunductors vary as per the nature of the material of cunductor vary.
●Temperature.
When temperature increase , Resistance also increase.

Resistivity,ρ=RAlρ=20×3.14×
(.15×10-3)22=7.065×10-7ohm-met