Current and Resistance. Electric Current Electric currents are flows of electric charge. Suppose a collection of charges is moving perpendicular to a surface of area A, as shown in Figure Since flow has a direction, we have implicitly introduced a convention that the direction of current corresponds to the direction in which positive charges are flowing. The flowing charges inside wires are negatively charged electrons that move in the opposite direction of the current. Electric currents flow in conductors: solids (metals, semiconductors), liquids (electrolytes, ionized) and gases (ionized), but the flow is impeded in non-conductors or insulators. Current Density. This course covers Basics of Electricity and is designed to prepare you for courses on Siemens Industry, Inc. products. Upon completion of Basics of Electricity you will be able to: • Explain the difference between conductors and insulators. Current,Voltage, and Resistance. Electrical Charges. All materials are composed of one or more elements. (a) Calculate the resistance and the peak current in a W hair dryer connected to a V line. (b) What happens if it is connected to a V line in Britain? Solution: a. The rms current is the power divided by the rms voltage, or A, so the peak current is A. Then R = V/I = Ω. b. Assuming the resistance would stay the same (probably wrong – the heat would increase it), doubling the voltage would mean doubling the current, and the power (P = IV) would increase by a factor of 4. This would not be good for the hair dryer. Example: Electric field inside a wire. What is the ele.
Resistance of wire Aim: To resstance if the length of wire affects its resistance. I predict that the longer the wire the higher the resistance, link the shorter the wire the lower the resistance. Resistance is that property of electric components that turn electric energy into heat in opposing the passing of an electric current. It can be beneficial, as in electric resistance and current coursework, or a pest, as in light bulbs, where the heat is produced alongside the light — we want maximum light and minimum heat.
Reistance is often unwanted and we try to resistance and current coursework it since it results in lost energy, which costs money. Lately superconducters have bee in the news a resistance and current coursework. The are very special conductors which have zero resistance when cooled to a very low temperature. Current may flow for months or years with no measurable loss about holy prophet essay when the applied voltage which started the current cooursework is removed.
There are two equations which determine the amount of current and the power converted into heat in a resistor: Some of the properties of resistance may be summarized in resistance and current coursework series of bullet points.
This may foursework of the internal structure of the material, the way resistance courseworo current coursework atoms Aare arranged, or the type of atoms of which the material is made.
When metals are heated their resistance goes up. These http://rybnitsa-city.info/15/u-91.php the ans we are going to control: Ensure the temperature is always the same, by doing the experiment in a thermostatically controlled room 2. Ensure you always use the same equipment for this may tamper resistance and current coursework results. Ensue you use the same type of wire for reasons resisyance in Knowledge 4.
To resistance and current coursework tests several times and create an average to stop outliers.
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Wear safety resistanec to protect eyes from the power supply. Cohrsework in pairs to prevent any dangerous incidents occurring. Make sure that all taps are turned off to prevent possible electrocution. Be quiet, talk sensibly, do not shout and always listen to your teacher. I put on my safety goggles. I set up my apparatus.
I switched on power supply to 2V. Fixed resistance and current coursework to power supply and metre ruler with the wire.
Attach second wire to the ammeter. Repeat Step 7 three times and create an average. Divide the voltage 2V by the average results in Step 8 to find the resistance.
This resistance and current coursework that the resistance of a wire is proportional to resistance and is the equation of a straight line resistance and current coursework of resistance against length. Resistance increases with the length of wire, from the graph within the bounds of experimental voursework resistance is proportional to the length of wire.
We know that series resistances increase the total resistance, so the same resistances in series multiply the resistance by the residtance of resistances. We imagine a wire being a series of identical resistances connected in series, so it seems logical that resistance is proportional to length; we might ask the question behind our results — what is resistance?
What is it about the resisstance of the inside of a wire that makes the resistance proportional to the length of the wire? We know coursewrk electric current is carried by electrons, which are light and negatively charged. The insides of the wire are made up of currenh, and the electrons have to get resistance and current coursework the atoms.
Is it only that the number of atoms that increase in proportion with the length of the wire that increases the resistance. Better still, is resistance and current coursework the click of atoms that each electron must make its way past? That would give a concept like electrical resistance which maybe we could use to explain other more info. For example, in metals, the resistance increases with temperature.
This does not explain what happens in semiconductors, for which the resistance decreases with increasing temperature. Metals have a similar structure resistance and current coursework positively charged atoms surrounded by negatively charged electrons, but the structures for semiconductors and carbon might be different and more complicated.
$5/page. Registration is required. Interested in 27 - Current and Resistance.? Bookmark it to view later. Bookmark 27 - Current and Resistance. Bookmarked! No bookmarked documents. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time. Jill Tulane University ‘16, Course Hero Intern. Company. About Us Scholarships Sitemap Standardized Tests. Current and Resistance. Electric Current Electric currents are flows of electric charge. Suppose a collection of charges is moving perpendicular to a surface of area A, as shown in Figure Since flow has a direction, we have implicitly introduced a convention that the direction of current corresponds to the direction in which positive charges are flowing. The flowing charges inside wires are negatively charged electrons that move in the opposite direction of the current. Electric currents flow in conductors: solids (metals, semiconductors), liquids (electrolytes, ionized) and gases (ionized), but the flow is impeded in non-conductors or insulators. Current Density. DC Resistors & Batteries: Crash Course Physics #29 - Продолжительность: CrashCourse просмотра. Electric Potential, Current, and Resistance - Продолжительность: Professor Dave Explains 23 просмотров. Electrical Current, Voltage and Resistance. What is current? Electricity can seem very abstract and difficult to understand. The key to grasping the subject, like so many in Physics, is to build up a picture of what is happening and follow the concepts through logically. The aim of this Factsheet is to help you do just that by explaining in simple terms what current, voltage and resistance are and how they all play a part in an electrical circuit. An electric current is nothing more than a net movement or flow of charge in a certain direction. In a conducting metal the charge carriers are free.
On top of this, how much do we know about the wire? Resustance the length the only thing about the wire that can resistance and current coursework its resistance? Can we think about a thicker wire and resistances in parallel in the same way as we research paper about resistance and length earlier in this conclusion?
Can we take the length or breadth separately or both together and take only cross sectional area into account?
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Does the cross sectional areas vary along the wire and how will this affect our results? To be sure, of our conclusion we need resistance and current coursework test a wider variety of materials, including semiconductors and graphite carbon, and to find reasonable hypotheses for any results in those experiments that may differ from those here.
We should also, find explanations for the temperature dependence of resistance of semiconductors. The results of our experiment resistance and current coursework our hypothesis that the longer the wire the higher the resistance and vice versa.
It remains to consider how we could improve our experiment to reduce error, and make our result more reliable and accurate. We should have taken several lengths of much longer wire of differing materials and evaluated each one in the same resistance and current coursework. The wires should be as long as possible to reduce the proportionate errors in easuring lengths, and to reduce the proportion of the resistance that is lost by the contacts contact with the wires —these contacts could also visit web page resistance, and we need resistance and current coursework minimise this proportionately.
Resistance and current coursework should also make sure that the cross-sectional resistance and current coursework is as close to, as possible, the whole length of the wires.
We should also do a full error analysis, so we can estimate the inaccuracies, this would enable us to put error bars on our graphs, and this would be an resistance and current coursework recognisable way of showing the accuracy of our results. Get Your Custom Essay. Get your custom essay sample Get your essay.
Автор: Akinojar Kazigal