Electric circuits || Resistance and thickness of wire
Revise calculating current, measuring potential difference and energy transfer. Find out about charge, resistance and ohms law with BBC Bitesize. I meant that the resistance would change for each length of the material so for isnt a resistance against length graph always meant to be of positive gradient?. At a constant temperature the resistance of a particular material depends on: What does your graph indicate about the relationship between length and.
Current and resistance
Discussion Overall, my results are very consistent with my predictions. Most of the data points were on, or very close to, the line of best fit.
- An Investigation Into the Resistance of a Wire - GCSE Physics Coursework
There are a few data points that are farther away from the line of best fit than the others, but they are still consistent with the general trend. There are no anomalous results that I would consider to be far away from the line of best fit.
There are possible sources of error that might have led to inconsistent results, such as a kink in the wire. This would have prevented the area of the wire from remaining constant and would have affected my results.
However, I made sure that the wire remained straight throughout the experiment. I think that the range of my results was sufficient enough for me to draw a valid conclusion about how the length of the wire affected the resistance. This was because I could plot a graph and show the general trend. However, I think that unless I had specialist equipment the results would be distorted because the wire would eventually get very hot.
Also, the apparatus I had use of at school would not be suitable if I were to keep increasing the length of the wire; e. I think my method could have been improved to produce results that were even more consistent.
Resistance and Resistivity
I could have considered using a new piece of wire each time in order to regulate the temperature more stringently. Using the same piece of wire throughout the experiment meant its temperature rose slightly over time, which may have affected my results.
The colors reveal information about the resistance value. Perhaps you're doing a lab and need to know the resistance of a resistor used in the lab. Use the widget below to determine the resistance value from the colored stripes.
Check Your Understanding 1. 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.
Current, voltage and 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.
This is reflected in the equations: At low temperatures some materials, known as superconductors, have no resistance at all.
Resistance in wires produces a loss of energy usually in the form of heatso materials with no resistance produce no energy loss when currents pass through them. Ohm's Law In many materials, the voltage and resistance are connected by Ohm's Law: These materials are called non-ohmic. We'll focus mainly on ohmic materials for now, those obeying Ohm's Law. Example A copper wire has a length of m and a diameter of 1.
If the wire is connected to a 1. The V is the battery voltage, so if R can be determined then the current can be calculated. The first step, then, is to find the resistance of the wire: L is the length, 1.
Electric circuits || Resistance and length
The resistivity can be found from the table on page in the textbook. The area is the cross-sectional area of the wire. This can be calculated using: The resistance of the wire is then: The current can now be found from Ohm's Law: It has units of Watts.
Batteries and power supplies supply power to a circuit, and this power is used up by motors as well as by anything that has resistance. The power dissipated in a resistor goes into heating the resistor; this is know as Joule heating. In many cases, Joule heating is wasted energy.
In some cases, however, Joule heating is exploited as a source of heat, such as in a toaster or an electric heater. The electric company bills not for power but for energy, using units of kilowatt-hours.
It does add up, though. The following equation gives the total cost of operating something electrical: Try this at home - figure out the monthly cost of using a particular appliance you use every day. Possibilities include hair dryers, microwaves, TV's, etc.#10 Resistance of wire per cm using ohm's law - class 12 ( PRACTICAL) - Rathour Classes
The power rating of an appliance like a TV is usually written on the back, and if it doesn't give the power it should give the current.
Anything you plug into a wall socket runs at V, so if you know that and the current you can figure out how much power it uses. The cost for power that comes from a wall socket is relatively cheap.