Ohm's Law: Electrical Conductivity and Resistence

Numerous factors influence electrical conductivity and resistance, two of them are temperature and length of the wire (these are external factors). Electrical conductivity is defined as the property used to describe how well materials allow electrons to flow, and the degree to which a specific material conducts electricity., Electrical conductivity is calculated as the ratio of the current density in the material to the electric field that causes the flow of current. The SI unit of electrical conductivity is Siemens per meter (S/m). Electrical conductivity is also commonly represented by the Greek letter σ (sigma), but κ (kappa) (especially in electrical engineering) or γ (gamma) are alsowhich are occasionally used. Electrical resistivity quantifies how strongly a specific material opposes the flow of electric current. Electrical 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 (Ω⋅cm) are also in use.

There are formulas to calculate electrical conductivity and resistivity. Conductivity is defined as the inverse of resistivity (a high conductivity means a low resistance), I=V/R or current equals voltage over resistance. This is known as Ohm’s Law. Electrical resistance is calculated by the formula, R=V/I or resistance equals voltage over current. Ohm’s law however does not hold true if temperature changes. Materials that obey Ohm’s law are known as ohmic or linear because the potential difference across it varies linearly with the current. In addition, whether or not a material obeys Ohm’s law its resistance can be described in bulk resistivity. Furthermore, over sizable ranges of temperature, this temperature depe...

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...ature, for example if temperature increases, the resistance, and conductivity value change.

3. Ohm’s Law is also subject to a specific amount of pressure on the substance. For example placing a conductor under tension (a form of strain), causes the length of the section of conductor under tension to increase causing the cross-sectional area to decrease, hence changing the value of resistivity and conductivity.

There are formulas to calculate electrical conductivity and resistivity. Conductivity (s) is defined as the inverse of resistivity (a high conductivity means a low resistance), I=V/R or current equals voltage over resistance. Electrical resistance is calculated by the formula, R=V/I or resistance equals voltage over current.

The objective of this study is to evaluate the effects of wire length and temperature of wire on electrical conductivity and resistivity.