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Investigating One Factor Which Affects the Resistance of a Wire

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Introduction

Investigating One Factor Which Affects the Resistance of a Wire Theory For this investigation I have to look at the factors which affect resistance in a wire and chose one to investigate. Resistance is the amount that a conductor resists the movement of electrons and it is measured in ohms (?). Resistance occurs when electrons moving in a metal conductor collide with atoms in the wire and give up energy. The energy the electrons give up is converted into heat. Superconductors have no resistance to the flow of electric charges. Copper, which is a good conductor, has a low resistance. Silicon, which is a semiconductor, has a higher resistance. Insulators, like glass or wood, have a very high resistance and it's nearly impossible for electric charges to flow through them. The idea of resistance is simply how difficult it is for the electrons to move through a material. The more difficult it is, the more energy they lose in the material on their travels. Ohm's Law for resistance states that 'The current flowing through a metal is proportional to the potential difference (current used) across it (providing the temperature remains constant). I am going to test this law. ...read more.

Middle

To collect accurate data I will do the following: * record readings to two significant figures * measure length of wire accurately * make sure there is minimum kinks in the wire which would affect the length * make sure the current is the same throughout the experiment The length of wire will have a range from 0.1 meters to 1 meter. I will have to keep the current constant at about 0.6 amps. Safety To insure that I or anyone else, don't get hurt, I will take the following precautions: * I won't touch the wire in case it's hot and I get burnt or in case I get a shock * I'll turn the switch off when I'm writing down results so it doesn't heat up * I'll wear safety goggles in case the wire snaps and hits me in the eye * I'll bend the wire at the edges so there are no sharp ages I could cut myself on * I will sellotape the wire down so it doesn't bounce up and hit someone * I'll keep flammable materials away from the circuit Recording the Data This is the table I will use to record the data. ...read more.

Conclusion

some time after each reading to let the wire cool down; - use a digital ammeter and - use a more accurate voltmeter. Why the Length Affected the Resistance The length of the wire affected the resistance because the longer the wire, the more atoms the electrons collided with resulting in the loss of more energy. short wire long wire electron atom As you can see the from the diagrams, there are more atoms for the electrons to collide into in the longer wire than there are in the short one, hence more energy being lost. There is little resistance in the leads running electricity to the wire because they are made out of copper. Copper is a very good conductor and electrons can flow through it without colliding with many atoms. Conclusion I have found out in this experiment that: - as the length of a wire increases so does the resistance. - Ohms Law, which states that the resistance of the wire is proportional to the length, is correct due to the fact that as the length of my wire increased so did the resistance e.g. wire length 0.3m, resistance 0.6 ? wire length 0.6m, resistance 1.21 ? These points also prove my predictions were correct. ?? ?? ?? ?? 1 ...read more.

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