Resistance and Resistivity
Thus By increasing length of conductor, It's Resistance increases. Hence, potential difference between nearest points (along axis of conductor) in conductor. Â· Ï = the resistivity of the material of which the conductor is made (Î©m) Essay about Relationship Between the Resistance and the Length of a Wire. How the dimensions of a conductor affect its resistance. Resistance is proportional to length and inversely proportional to cross sectional area. Formulae and.
Household circuits are often wired with two different widths of wires: Thus, gauge wire has a wider cross section than gauge wire. A Amp circuit used for wall receptacles should be wired using gauge wire and a Amp circuit used for lighting and fan circuits should be wired using gauge wire.
Explain the physics behind such an electrical code. See Answer A gauge wire is wider than gauge wire and thus has less resistance.
The lesser resistance of gauge wire means that it can allow charge to flow through it at a greater rate - that is, allow a larger current. Thus, gauge wire is used in circuits which are protected by Amp fuses and circuit breakers. On the other hand, the thinner gauge wire can support less current owing to its larger resistance; it is used in circuits which are protected by Amp fuses and circuit breakers.
Based on the information stated in the above question, explain the risk involved in using gauge wire in a circuit that will be used to power an ampere power saw. Thus, gauge wire can safely support a circuit that uses an appliance drawing up to 20 Amps of current. In fact, a Amp circuit is protected by a fuse or circuit breaker that will flip off when the current reaches 20 Amps.
If a gauge wire was used on the same circuit, then the breaker would allow up to 20 Amps to flow through it. It could overheat and thus lead to the risk of fire. A Amp circuit should never be wired using gauge wire.
Determine the resistance of a 1-mile length of gauge copper wire. The pressure difference between two sides of a pipe, not the pressure itself, determines the flow through it. For example, there may be a large water pressure above the pipe, which tries to push water down through the pipe. But there may be an equally large water pressure below the pipe, which tries to push water back up through the pipe.
If these pressures are equal, no water flows. In the image at right, the water pressure below the pipe is zero. The resistance and conductance of a wire, resistor, or other element is mostly determined by two properties: In the same way, a long, thin copper wire has higher resistance lower conductance than a short, thick copper wire.
Materials are important as well. A pipe filled with hair restricts the flow of water more than a clean pipe of the same shape and size. Similarly, electrons can flow freely and easily through a copper wire, but cannot flow as easily through a steel wire of the same shape and size, and they essentially cannot flow at all through an insulator like rubberregardless of its shape.
Resistance in Conductors
The difference between copper, steel, and rubber is related to their microscopic structure and electron configurationand is quantified by a property called resistivity. In addition to geometry and material, there are various other factors that influence resistance and conductance, such as temperature; see below.
Conductors and resistors[ edit ] A 6. An ohmmeter could be used to verify this value. Substances in which electricity can flow are called conductors. A piece of conducting material of a particular resistance meant for use in a circuit is called a resistor. Conductors are made of high- conductivity materials such as metals, in particular copper and aluminium. Resistors, on the other hand, are made of a wide variety of materials depending on factors such as the desired resistance, amount of energy that it needs to dissipate, precision, and costs.
Ohm's law The current-voltage characteristics of four devices: Two resistorsa diodeand a battery. The horizontal axis is voltage dropthe vertical axis is current. Ohm's law is satisfied when the graph is a straight line through the origin.Effect of length ,diameter ,area on value kinenbicounter.infoance
Therefore, the two resistors are ohmic, but the diode and battery are not. For many materials, the current I through the material is proportional to the voltage V applied across it: