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Factors affecting the resistance of a conductor
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Recommended: Factors affecting the resistance of a conductor
The Relationship Between Length, Width and Resistance of a Wire
Aim: To investigate how the length and width of a wire affects the
resistance of the wire.
What is resistance?
Electricity is conducted through a conductor, in this case wire, by
means of free electrons. The number of free electrons depends on the
material and more free electrons means a better conductor, i.e. gold
has less resistance. For example, gold has more free electrons than
iron and, as a result, it is a better conductor. The free electrons
are given energy and as a result, move and collide with neighbouring
free electrons. This happens across the length of the wire and thus
electricity is conducted. Resistance is the result of energy lost as
heat. It involves collisions between the free electrons, the fixed
particles of the metal, other free electrons and impurities. These
collisions convert some of the energy that the free electrons are
carrying into heat which means that electrical energy is lost.
Apparatus: I will be using: - An Ammeter
- Voltmeter
- Variable resistor
- Power Supply
- Various diameters of wire
- Crocodile clips
- Metre ruler
[IMAGE]
Diagram:
Secondary Source - (Obtained in A-level PHYSICS by Roger Muncaster.
Page 536.)
The electrical resistivity of a material is defined by
R= ÏL/A
Where
· R = Resistance of some conductor(Ω)
· L = Length of the conductor(m)
· A = Area of cross - section of the conductor (m²)
· Ï = the resistivity of the material of which the conductor is made
(Ωm)
The experimental determination of the resistivity of a material
involves measuring the resistance of a specimen of the material. The
specimen must be regularly shaped in the form of a wire; its diameter
should be measured at six different points.
Variables and Controls:
The variables that I will be using are the length and diameter of the
wire.
I also decided to use a wooden block to keep hold of the wire, because
[IMAGE] Most reactive Potassium Sodium Lithium Calcium Magnesium Aluminium Zinc Iron Tin Lead Copper ------ Silver Gold Potassium Least reactive Electrical flow through metals work like this: the current in the metal is carried by electrons and will only flow if there charges which can move freely.
Do you ever wonder about what happens with electricity? In the article “Energy Story” written it tells you about atoms and what things need to have to be that type of object. In the article “Conducting Solutions” by Rodney Schreiner tells you about solutions and the reactions to them with electricity. In the video clip “Hands-on Science with Squishy Circuits” by AnnMarie Thomas it tells you about how simple play dough can hold electricity.
Electricity is an interesting subject. There is so much you can learn from it, like how our lights turn on or how we make cell phones. This is all a mystery until we finally get a little bit of information in our brains. I've just read two articles, "Energy Story" and "Conducting solutions". I also watched a video called Hands-on Science with Squishy circuits. I learned so much valuable information from these resources.
· 6V Filament Lamp. · 7 Wires. Definitions: Ammeter - This is a device that measures the current of electrons in Amps.
Conduction, convection and radiation are the three methods through which heat can be transferred from one place to another. The (www.hyperphysics.com) first method is the conduction through which heat can be transferred from one object to another object. This process is defined as the heat is transmitted from one to another by the interaction of the atoms and the molecules. The atoms and the molecules of the body are physically attached to each other and one part of the body is at higher temperature to the other part or the body, the heat begins to transfer. A simple experiment through which conduction can be understood easily is as follows. First of all, take a metallic rod of any length. Hold the rod in the hand or at any stand made up of the insulator so that the heat does not transfer to the stand. Heat up the one end of the rod with the help of the spirit lamp. After sometime, touch the other end of the end, the other end of the becomes heated too and the temperature of the other end of the rod has also increased. Although only one end of the rod is heated with the spirit lamp, but the other end of the rod has also been heated. This is represents that the heat has been transferred from one end of the rod to the other end of the rod without heating it from the other end. So, the transformation of the heat is taking place. This process is called the conduction. Conduction is a process which is lead by the free electrons. As the conduction happens occurs only in the metallic materials, the reason for it is that the metals has the free electrons and they can move freely from one part of the body to another part of the body. These electrons are not bounded by the nucleus so, they can move easily. And when the temperature of the ...
Resistance is what links current and voltage together. Resistance is the property of a substance which opposes the flow of current is called its resistance. A substance which possesses low resistance is said to be a good conductor of electricity; poor conductors are those which posses high resistance. In 1827, George Simon Ohm, a German scientist discovered the relationship between the potential difference (voltage) applied between the ends of a conductor and the current passing through it. This important relationship is now known as ‘Ohms law’ which can be stated as follows: ‘The current passing through a conductor is directly proportional to the potential difference applied across its ends, provided that the temperature and other physical factors of the conductor are kept constant.’
of the atoms, so if there are more or larger atoms then there must be
the number of wires used, each bit of wire was cut into lengths of 30
I have done a diagram below to help me understand this. Material/resistivity : Different wires composed of different metals will have differing
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All of the experiments we performed utilized a voltmeter, a breadboard, some wire, two different types of voltage sources, and resistors with a range of resistance. All components were plugged into the breadboard for ease of testing purposes using the voltmeter.
Circuit analysis is used to determine the missing components of a circuit using the information giving. It combines Kirchhoff’s law, Ohm’s law, and our problem solving skills to solve complex circuits. There are many different methods to approach solving a circuit, but one of the key ideas to keep in mind is that once you discover 2 of your unknowns (current, resistance, or voltage) you can use Ohm’s law to solve for the third unknown. Another trick to solving a circuit is starting from one corner/side and working your way through to the other side.
Numerous factors influence electrical conductivity and resistance, two of them are temperature and length of the wire (these are external factors). Electrical conductivity is defined as the property used to describe how well materials allow electrons to flow, and the degree to which a specific material conducts electricity., Electrical conductivity is calculated as the ratio of the current density in the material to the electric field that causes the flow of current. The SI unit of electrical conductivity is Siemens per meter (S/m). Electrical conductivity is also commonly represented by the Greek letter σ (sigma), but κ (kappa) (especially in electrical engineering) or γ (gamma) are alsowhich are occasionally used. Electrical resistivity quantifies how strongly a specific material opposes the flow of electric current. Electrical resistivity is commonly represented by the Greek letter ρ (rho). The SI unit of electrical resistivity is the ohm⋅metre (Ω⋅m) although other units like ohm⋅centimetre (Ω⋅cm) are also in use.
As you across a period, of metals, the reactivity decreases. The reactivity decreases because the atomic radius decreases as well. As the atomic radius increases, ionization energy and electronegativity increase, because the effect of shielding isn't as great as it is on smaller atoms. A larger ionization energy means that the atom is less prone to giving electrons and a larger electronegativity means that the atom has more of an attraction on other atoms'