investigating the factors that effect the resistance on a length of nichrome wire

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Niall Bradley 12L

An Investigation to find the factors which affect the resistance of a length of nichrome wire

Aim: To find out the effect of changing the length and or thickness of a piece of Nichrome wire on resistance.

Background Knowledge

There are four main factors that can affect the resistance; they are
the
length, this can affect it because the number of atoms is
different as the length changes making the rate of energy transfer
differ. Another factor is the
cross sectional area, this can affect it
as there is either less or more space as the area increases or
decreases for the atoms to collide with each other, furthermore the
material can affect it as each metal or substance have different
atoms and the atomic structure is different. Finally the
temperature can affect the resistance as the temperature increases the atoms energy increases giving it the power move faster whereas in colder conditions there is less energy and the opposite affect would take place, although temperature will be uncontrollable in the environment we will perform the experiment in. The other factors could be; Light, wire tension, gravity and magnetic influence.

Resistance is a force which opposes the flow of an electric current around a circuit so that energy is required to push the charged particles around the circuit. The circuit itself can resist the flow of particles if the wires are either very thin or very long. Resistance is measured in “ohms”. The symbol for an ohm is ‘’. A resistor has the resistance of one ohm if a voltage of one volt is required to push a current of one amp through it.

R=K x L/A

R= Resistance - measured in Ohms (Ω)

K = K factor (the type of material)

L = Length of wire- measured in cm or m

A = Area of cross section

Current is the flow (movement) of electric charge. Electric current is measured using an ammeter and is measured in “amps”. Symbol for amps is “A”. 

I=Q/T

I   = Current- measured in ‘amps’

Q = Quantity of charge- measured in ‘coulombs’

T = Time – measured in ‘seconds’

Voltage is the measurement of the potential for an electric field to cause an electric current in an electrical conductor, specifically; voltage is equal to energy per unit charge. It is measured in volts (V) and by using a voltmeter.

To make a current flow through a resistance there must be a voltage across that resistance. Ohm's Law shows the relationship between the voltage (V), current (I) and resistance (R).

The relationship between Voltage, Current and Resistance in any DC electrical circuit was firstly discovered by the German physicist Georg Ohm, (1787 - 1854). Georg Ohm found that, at a constant temperature, the electrical current flowing through a fixed linear resistance is directly proportional to the voltage applied across it, and also inversely proportional to the resistance

Voltage is the electrical force present causing the charge to move, and it is measured in volts. This gives rise to energy transfer.

Electrical energy = Voltage x quantity of charge

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Energy= Volts x Columbs

Calculating thickness of wire:

As it is difficult to find the thickness of one strand of wire without an advanced piece of equipment. I will find the length of 100 wires and divide it by 100.

Circuits in series and parallel:

Series – Chain Link:

The Total resistance= R1+R2+R3

            (RT)

The total length resistance=L1+L2+L3

        (LT)

Parallel- Ladder form:

RT= Product / Sum

              ...

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