Question

deriveexpression for resistance and resistivity and it's SI unit

Answer 1

Answer:

SI unit of resistivity is Ohm and denoted as Ω. Consider a conductor of length l and cross sectional area A. Assume that there are n numbers of free electrons per unit volume of the conductor. ... The ρ is called specific resistance or the resistivity of a conductor of a material

Answer 2

Let R be the Resistance .

Let p be the Resistivity .

R is inversly proportional to A (area )

R is directly proportional to L ( length)

Combining both .

R is directly proportional to L/A

Removing proportionality constant

R = P*L/A

hence this is the mathematical relationship between Resistance and Resistivity .

Si unit of resistance is ohm and of resistivity is ohm metre