What is resistivity ? Write its unit. On what factors do resistivity depend? (AU India - 2011)

Explanation

`rArr` At given temperatur resistance of material,
`R = rho (l)/(A)`
`therefore rho = (RA)/(l) `
`rho` = resistivity of conductor
`rArr` Definition : Resistance of conductor having unit length and unit cross-section area is called resistivity or specific resistance.
`rArr` Value of resistivity depend on type of material of conductor, temperature and pressure.
`rArr` It does not depend on dimension of conductor. 11
`rArr` Unit = `Omega` m(Ohm. m) and dimensional formula `= M^(1) L^(3) T^(-3) A^(-2)`.