What affects the resistance of a wire?
Physics coursework* In this experiment I will be describing the potential difference (or voltage) as the electrical 'pressure' pushing the charges around the circuit. I know though that some of this pressure is dropped while pushing the charges through any form of electrical resistance in the circuit. So, the potential difference across the two ends of a resistance is just the pressure dropped across the resistance. WHAT IS RESISTANCE? Current is a flow of tiny, negatively charged electrons through a conductor Like a metal wire, Metals are particularly good at carrying a current, because they have lots of "free" electrons. This means electrons which are not bound onto a particular atom in the wire, will move through the wire if you drop the pressure across its ends. The number of free electrons depends on the material, the more electrons flowing freely the better the 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. The property of the conductor restricts the flow of electricity through it. Resistance is the result of electrons; motion is impeded. It involves collisions between the free and the fixed atoms of the wire material, and other free electrons and impurities causing less current to flow. These collisions convert some of
What affects the resistance of a wire?
What affects the resistance of a wire? Aim: In this experiment I will be finding out the resistance of a wire in which its length is the variable. I will be investigating the process of how much the resistance increases due to the increase the length of the wire. (Constantan Wire) Planning: Resistance is the property of an electrical conductor, to work against the flow of the current and change some of the electrical energy into heat. The quantity of resistance in an electric circuit determines the amount of current flowing in the circuit for any given voltage applied to the circuit, according to Ohm's law. To find the value of resistance, the equation Resistance (?) = Voltage (V) / Current (A) is used. Also, the temperature can determine the resistance of the resistor. It is not just the resistor that causes resistance in the circuit, as any component in the circuit causes resistance. The 3 variables are the length, diameter of the wire, the material the resistor is made out of and the temperature of the wire. I used the same The length of the wire will make a difference because there will be more atoms for the current to pass through so there will be more resistance in the wire. The diameter of the wire will make a difference as the thicker the wire, the easier the current will be able to pass through it, as there is more room within the wire. The material the
What Factors affect the resistance of a wire?
GCSE Physics Coursework by Anna Lambregts What Factors affect the resistance of a wire? Aim The Aim of this experiment is to investigate the ways in which thickness (or rather the cross sectional area) affects the resistance of a wire, how it affects it, and why this happens. Prediction I predict that the thickness area of the wire will affect the resistance of the wire, as the thickness gets greater, the resistance decreases. I also predict that the cross sectional area and resistance are inversely proportional to each other. Where the thickness is concerned, the thickness and resistance are directly proportional to each other, this I mean that as the thickness increases, the resistance decreases at the same rate. Therefore: Thickness Resistance x y x + 1 y - 1 Theory I am basing my prediction on what I know about how the cross sectional area affects the resistance of a wire. I know that metals conduct electricity because the atoms in them do not hold on to their electrons very well, and so, creating free electrons, carrying a negative charge to jump along the line of atoms in a wire. Resistance is caused when these electrons flowing towards the positive terminal have to 'jump' atoms. The smaller the cross sectional area of the wire, the less channels of electrons in the wire for current to flow, as the energy is not spread out as much in
What factors affect the resistance of a wire?
An Investigation into the Electrical Resistance of Wires Introduction My Physics coursework is about the electrical resistance of wires and to see what affects the resistance. Electrical resistance is the measure of the degree to which an object opposes the passage of electrical current. Ohm's Law states that at a constant temperature, the resistance is the amount if current flowing for any given voltage. This can be written by the formula: R is the resistance in Ohms V is the voltage in Volts I is the current in Amperes Scientific Background A metal consists of a grid of atoms, each with a shell of electrons. The outer electrons are free to separate from their own atoms and travel through the grid, making the metal a conductor. When an electrical potential (a voltage) is applied across the metal, the electrons drift from one end of the conductor to the other under the influence of the electric field causing electrical conduction. These electrons can collide into impurities, the lattice and other free electrons and so cause resistance. A rise in temperature causes the atoms to vibrate more strongly, creating even more collisions, making it more difficult for the electrons to get through and so increasing resistance. Variables The possible independent variables for the investigation are: - Thickness (Diameter, Circumference, Radius or Area) of wire: The cross
What factors affect the resistance of a wire?
What factors affect the resistance of a wire? Although the current and the potential difference (voltage) measure different things, they are related to one another. If a battery is connected to a length of wire, it is possible to measure the current through the wire using 1, 2, 3 or 4 cells. By doing this, it is possible to find a simple relationship between the potential difference across the ends of a wire and the current through it. This being that doubling the potential difference doubles the current. Repeating the investigation for other types of wires provides results displaying a similar relationship between potential difference and current. Voltage current graphs are always straight lines through the origin, although the slopes are different. In 1826 a German physicist called Georg Ohm first discovered this relationship between potential difference and current. Ohm's law states that: "Provided the temperature and other physical factors remain constant the current through a wire is proportional to the potential difference across its ends." If the potential difference across the ends of a wire is divided by the current through it, we get a constant figure for a given piece of wire. This figure is the resistance of the wire and represents the wires opposition to current. Ohm's law can be expressed by the formula I= V/R, where I is the current in amps, V is the
What Factors Affect the Resistance of a Wire?
What Factors Affect the Resistance of a Wire? Hypothesis I am going to investigate what factors affect the resistance of a wire. There are three main factors which affect the resistance of a wire: The material of the wire. (What the wire is made out of) The length of the wire. The thickness of the wire. (The diameter of the wire) 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. e.g. The filament across an electric light bulb. 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. George Ohm discovered that the emf of a circuit is directly proportional to the current flowing through the circuit. This means that if you triple one, you triple the other He also discovered that a circuit sometimes resisted the flow of electricity. He called this resistance. He then came up with a rule for working out the resistance of a circuit: V/I = R or V - volts I - current R - resistance To begin with I am going to investigate which materials put up the highest resistance and I will combine it with the investigation about which length puts up the
What Factors affect the resistance of a wire?
Plan. In this investigation I will be exploring the factors that affect the resistance of a wire. 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 equipment I will use to carry out each experiment is: -A power pack To give the circuit electrical energy.. -An ammeter To measure the current and in turn work out the resistance of each wire. -A voltmeter To measure the voltage and use it with the current to fond the resistance of each wire. -Selection of wires different materials, widths and lengths to compare the ways in which they affect the resistance. To connect the other equipment together and to complete the circuit. -Crocodile clips To connect the wire being investigated to the rest of the circuit and to change the length of the wire i.e. I will clip the wire to the length I want to measure. -1m ruler To measure the wire being tested to ensure a fair test. Here is a diagram of the circuit I will use to find the voltage and current readings of each length wire: I will be using Ohm's law, R=V/I, to find the resistance of each piece of wire. Method. To obtain results to compare the factors that affect the resistance of a wire, I am going to set up the circuit above, using a voltmeter in parallel to measure the volts and an ammeter in series to
What factors affect the resistance of a wire?
What factors affect the resistance of a wire? Aim: The aim of our experiment is to find out the different factors that affect the resistance of a wire. We will measure the affect of the length of the wire and its cross section on the resistance. Equipment: - Different thicknesses of Nichrome wire - Altmeter - Voltmeter - Power supply - Ruler - Circuit wires - Crocodile clips Diagram: Method: Set the apparatus up as shown in the diagram above on the left. The diagram on the right shows how I will connect the Nichrome wire, and measure it. Move the crocodile clips along the wire according to the desired length. When I am trying to find out the affect of length on resistance, I will move the crocodile clips along the wire every 5 centimetres, from 50 down to 0. I will move the crocodile clips around on the wire to ensure that I have a good connection, and that nothing will affect the reading that I take. When I am measuring the affect of cross sectional area on the wire, I will just change the thickness of Nichrome wire between the two connecting wires. Again, I will ensure that I have a good connection, to make sure I get an accurate reading. I can either take a direct Ohms reading, or I can use the following equation to get a resistance level: Resistance = Potential Difference / Current Ohms = Volts / Amps If I use the
What Factors Affect the Resistance of a Wire?
Monday 1st February Mark Jones Science coursework: The resistance of a wire Aims: In this investigation I am trying to determine what factors affect the resistance of a wire. Introduction: The factors that will affect the investigation are The conductivity (the opposite of resistivity) of a solid depends on the density of free electrons and how easily they can move through the crystal structure of the solid. Metals have lots of freely moving electrons. Other substances, such as glass, have few. Although all metals are pretty good conductors of electricity, they vary in how many free electrons are available and how easily they may move through the crystal structure of the metal. In a bit more detail, some factors that affect conductivity and resistivity in solids are: * Movement of electrons: In a conductor there are free electrons that are moving about randomly in all directions. When an electrical potential is applied there is a tendency for the electrons to move towards the positive charge, so while the motion of the electrons is still random, the average of all the movements is in that direction. * Electron energy levels: The electrons in a solid are at various energy levels. The energy of an electron may increase, but only by specific amounts, called quanta. An electron may be at one of
What is resistance?
GCSE Physics Coursework Theory What is resistance? Electricity is conducted through a conductor. The number of free electrons depends on the wire and more free electrons means a better conductor. The free electrons give lots of energy and then they collide with other free electrons. This happens across the wire and then electricity is conducted. Resistance is the result of energy loss as heat. The collisions turn the energy into heat. How is it measured? Resistance of a length of a wire is measured by the current and the voltage across a wire. Formulas - I = R = V = I x R Factors affecting Resistance * Length of a wire can affect the resistance of a wire because there are more atoms in a longer wire for the electrons to pass through. * Material of a wire can affect the resistance of a wire because some materials resist the flow of electrons more than others. * Thickness of a wire can affect the resistance of a wire because there is more room for electrons to pass through so the thicker the wire the less resistance. Ohm's Law The size of the electric current flowing through a conductor depends on the voltage across it, and the resistance of the conductor. When the voltage is increased, the current increases. The current is the same as the voltage if the temperature remains the same. The German physicist Georg Ohm formulated this in the 1920's. If the
