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Investigating the Resistivity of a Wire

In: Science

Submitted By shahadalwazzan
Words 589
Pages 3
Aims and objectives:

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The aim of this experiment is to know how does the length of the wire affects the wires resistance. Also measuring the voltage and current. A thin and a thick wire are used to get the results needed. There are three factors that influence the resistance of w wire which are, the thickness of a wire, temperature and length. Knowing those factors and measuring them will show how the experiment went.

Introduction:
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The resistance of a material is the extent to which is oppose the flow of current. “Electronics for today or tomorrow, 2nd Edition, Tom Duncan, page 8” Where as conductors have low resistance and inductors have high resistance. Further more resistance is measures with ohms. The main concept of the experiment is to investigate the difference in the resistance when having several lengths of a wire. The reason why different lengths of a wire affect the resistance is because the length of the will is increased which will also make the resistance increase as well, therefore electrons will have a longer distance to travel. Because of this the length of a wire should be proportional to the resistance. Conductors are good metals of electricity because they have low resistance which is why electrons get away easily just by applying the voltage. Furthermore, the resistance of a wire and the length of the wire both increase but the thickness of the wire decreases at the same time. Moreover, thin wires have high resistance but thick wires have low resistance. Due to Ohm’s law which stated that the resistance of a wire id directly proportional to its length and inversely proportional to its thickness.
Theory:
The theory of this experiment is that the resistance R in the circuit of a component is given by this equatio n:
V=IR
Where as: * V is the potential difference across the component. (Volts) * I is the current in the component. (Ampers) * R is the resistance. (Ohms)

The main factors that affect the resistance are the thickness of the wire, length of the wire and the temperature of the conductor and those factors also affect the current and voltage. The equation that gives the resistance of a wire is this equation:
R=pLA
Where as: * p is the resistivity (ohms) * L is the length (meters) * A is the cross-sectional area (meters2)

Circuit Diagram:

Recorded Data: * Table One (Thin Wire) | | | | | | | | | | Thin wire | | | | Wire Dia | length | V.res | V.wire | I | R |  | (mm) | (mm) | (V) | (V) | (A) |  | (m) | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | (av) | |

* Table Two (Thick wire)

| | | Thick wire | | | | Wire Dia | length | V.res | V.wire | I | r |  | (mm) | (mm) | (V) | (V) | (A) |  | m) | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

Graphs: * Graph Table One:

* Graph Table Two:

Precaution:
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Safety is the most important thing you should consider in any experiment. Therefore make sure that none of the wires are frayed and that the wires are all connected in the right way. Before starting the experiment see if there is any water close to any electrical equipment in any electrical experiment not just this one, having water near electrical equipment and electricity could be very dangerous. Wear goggles just incase any sparks might be produced during the experiment. Measuring the voltage of the wire needs full attention and being really cautious where as the wire might be hot. Stand during the experiment to be cautious not to be injured if anything brakes.
Percentage Of Error:

Conclusion:

Reference: * http://www.gcsescience.com/pe8.htm * http://www.123helpme.com/view.asp?id=148084 * http://luno2012.hubpages.com/hub/investigating-the-resistance-of-wire *

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