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for this essay I investigated Ohms Law. I investigated the effect...

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for this essay I investigated Ohms Law. I investigated the effect that the length and the thickness of wire had on the resistance.

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  • August 14, 2002
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Investigating Resistance

Electricity is the flow of electrons. Resistance is the slowing of this flow. Resistance will increase when there are more electrons for the current to collide with. It will also increase when the electrons are moving at a high speed. There are five main factors that affect resistance. These are

i.Length of wire

ii.Temperature of wire

iii.Voltage that is used to push current around circuit.

iv.Thickness of piece of wire.

v.Material.

i.If the length of the wire is increased, the resistance will increase. If the length of the wire is decreased, the resistance will decrease. This is because if the wire is increased from 10cm to 20cm the electrons will have more wire particles to collide with.

I.E ?

10 cm 20 cm

ii.As with all solids, liquids and gases, if the wire is heated, the particles will gain more energy and will move faster. Due to this the electrons will collide with the wire particles more frequently than if the wire was cool.

I.E ?

Cool Wire Heated Wire

iii.If the voltage in the wire is increased, the heat of the wire will increase. As with ii. the particles will move faster thus creating more collisions between the electricity particles and the particles in the wire.

I.E ?

2V 4V

iv.The thicker the piece of wire, the less resistance there will be. This is because the electrons have more space to move in. Therefore, there will be fewer collisions between particles and this will reduce the resistance.

I.E ?

26 SWG 24 SWG

v.As some materials are better conductors than others, this will obviously affect the resistance. This is why gold plugs are preferable in stereo systems.

Aim

To investigate what affects resistance. I have chosen to investigate length at 5cm intervals and thickness. I have chosen 24 SWG, 26 SWG and 28SWG (with 24 SWG being the thickest wire and 28 SWG being the thinnest).

Prediction

Ohms Law states: "The current flowing through a metal wire is...