Electricity has become very useful and has changed everyone’s life since the day it was discovered.What is Conductivity?
What is Resistance?
What is the best conductor of electricity?
What is Nichrome Wire?
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There are many factors that influence the electrical resistance in wires, going through a current in circuits. The length of the wire and the cross-sectional area are two very important variables. The flow of charge through wires is often compared to the flow of water through pipes. The resistance to the flow of charge in an electric circuit is analogous to the frictional effects between water and the pipe surfaces as well as the resistance offered by obstacles that are present in its path (The Physics classroom,2016)
The total length of the wires will affect the amount of resistance. The longer the wire, the more resistance that there will be. There is a direct relationship between the amount of resistance encountered by charge and the length of wire it must traverse. After all, if resistance occurs as the result of collisions between charge carriers and the atoms of the wire, then there is likely to be more collisions in a longer wire. More collisions mean more resistance.
The cross-sectional area of the wires will affect the amount of resistance. Wider wires have a greater cross-sectional area. Water will flow through a wider pipe at a higher rate than it will flow through a narrow pipe. This can be attributed to the lower amount of resistance that is present in the wider pipe. (The Physics classroom,2016) In the same manner, the wider the wire, the less resistance that there will be to the flow of electric charge. When all other variables are the same, charge will flow at higher rates through wider wires with greater cross-sectional areas than through thinner wires.[AR3]
Another formula that will be used is the resistance formula which will
(Physicsclassroom, 2016)
To work out the cross-sectional area of the wire, the formula
The wire that will be used in the experiment is nichrome 30 wire which has a radius of 0.000125m and also nichrome 22 wire, with a radius of 0.0346mm [AR4](3.46e-5m)
Ohm’s law deals with the relationship between voltage, current and resistance. Voltage is the difference in electrical potential energy. For example, if you have a simple circuit with a battery powering a lamp, the electrons will move from the negative side of the battery, through the lamp and then to the positive side. The voltage or the difference in electrical potential energy, between the positive and negative ends of the battery would be the amount labelled on the battery because the charge was used to move the electron around the circuit. A good analogy for voltage is a waterfall. The water at the top of the waterfall is similar to the negatively charged electrons and the water at the bottom of fall is similar to the discharged electrons. As the water flows from the top of the fall to the bottom it loses all of it gravitational potential energy just like the electrons losing their charge when they travel around the circuit. Current is the total amount of charge passing through a conductor over a period of time. The water analogy for current would be how fast the water is flowing or how much water is passing through a bit of river over a period of time. [AR5](Crash Course, 2016)
Ohm’s law can be summarised with
(Hyperphysics, 2016)
Since the results of the experiment will be recorded using a voltmeter and ammeter, the resistance will have to be calculated using ohms’ law re-arranged
(Hyperphysics, 2016)
Resistivity P (Ohm M) = and a resistivity coefficient 1.10?10-6a„¦m to 1.50?10-6a„¦m at 20A°C so this figure will be used in the resistance formula [AR6](Elert, 2016)
