10) What is resistivity? Derive its expression.
Answers
The electrical resistivity is the electrical resistance per unit length and per unit of cross-sectional area at a specified temperature. The SI unit of electrical resistivity is the ohm⋅metre (Ω⋅m). It is commonly represented by the Greek letter ρ, rho.
Answer:
resistivity:
Electrical resistivity and its inverse, electrical conductivity, is a fundamental property of a material that quantifies how strongly it resists or conducts electric current. A low resistivity indicates a material that readily allows electric current. Resistivity is commonly represented by the Greek letter ρ.
expressions:
Resistance R of a conductor depends on the length l and area of cross section A of the conductor Where, (rho) is called resistivity of the conductor it is also called as specific resistance. If we put l=1m andA=1sq.m. then we get, R=ρ. Therefore, R=ρ AL .
Resistance R of a conductor depends on the length l and area of cross section A of the conductor Where, (rho) is called resistivity of the conductor it is also called as specific resistance. If we put l=1m andA=1sq.m. then we get, R=ρ. Therefore, R=ρ AL .Thus, resistivity of a conductor is defined as the resistance of a conductor of unit length and unit area of cross section. The SI unit of resistivity is ohm metre. Resistivity is the characteristic property of material. It is different for different materials.
ρ=RA/l