Question 31
What is electrical resistivity of a material? What is its unit? Describe an experiment to study the factors on which the resistance of conducting wire depends.
Question 31
What is electrical resistivity of a material? What is its unit? Describe an experiment to study the factors on which the resistance of conducting wire depends.
Electrical resistivity (also known as resistivity, specific electrical resistance, or volume resistivity) is an intrinsic property that quantifies how strongly a given material opposes the flow of electric current. A low resistivity indicates a material that readily allows the movement of electric charge. Resistivity is commonly represented by the Greek letter ρ (rho). The SI unit of electrical resistivity is the ohm metre (Ω m) although other units like ohm centimetre (Ωcm) are also in use. Many resistors and conductors have a uniform cross section with a uniform flow of electric current and are made of one material. In this case, the electrical resistivity ρ is defined as:
ρ=R Al
where,
R is the electrical resistance of a uniform specimen of the material
l is the length of the piece of material
A is the cross - sectional area of the specimen. If A and l are given values of unity, then p is numerically equal to the resistance of a conductor having unit cross section and unit length. If R is in ohms, A in square centimetres, and l in centimetres, then ρ is in ohm-centimetres.
Electrical resistivity (also known as resistivity, specific electrical resistance, or volume resistivity) is an intrinsic property that quantifies how strongly a given material opposes the flow of electric current. A low resistivity indicates a material that readily allows the movement of electric charge. Resistivity is commonly represented by the Greek letter ρ (rho). The SI unit of electrical resistivity is the ohm metre (Ω m) although other units like ohm centimetre (Ωcm) are also in use. Many resistors and conductors have a uniform cross section with a uniform flow of electric current and are made of one material. In this case, the electrical resistivity ρ is defined as:
ρ=R Al
where,
R is the electrical resistance of a uniform specimen of the material
l is the length of the piece of material
A is the cross - sectional area of the specimen. If A and l are given values of unity, then p is numerically equal to the resistance of a conductor having unit cross section and unit length. If R is in ohms, A in square centimetres, and l in centimetres, then ρ is in ohm-centimetres.
