Resistance through wires.
Resistance through wires Introduction Electrical resistance is a measure of a materials opposition to the flow of an electric charge. Resistance is usually given the symbol 'R'. The unit for electrical resistance is the ohm. Ohm's law is the voltage drop (V) across a resistor proportional to the current running through it. The main causes of resistance to electrical flow in metal are imperfections impurities and temperature caused by the fact that electrons collide with the atoms creating heat. Aim: To find out how the length of a piece of wire affects the resistance. Variables Variable How I control it Material of wire Use the same material. Different materials have alternate atomic structures, conductivity i.e. inbuilt resistance, also some materials have more impurities than others. Diameter of wire use the same sample of wire the bigger the diameter the smaller the resistance temperature Don't leave the current running too long. Allow to cool if necessary and choose suitable voltage. The hotter the wire the resistance increases. Length of wire Change the length to see the differences. Apparatus: x power pack, leads, crocodile clips, meter rule, Ammeter, Volt meter and a length of wire Method: . Attached wire to meter rule. 2. Set up apparatus 3. With crocodile clips adjust the length of the wire that the current is running through and record
Electromagnetism Investigation.
Electromagnetism Investigation Physics - Electromagnetism Planning Previous Scientific Knowledge. When insulated wire is wrapped round an iron nail and the ends of the wire are connected to a battery the nail becomes capable of picking up iron filings and paper clips. This is called an electromagnet. The nail is magnetised by the current in the wire. If the battery is disconnected then the iron clips will fall off. This is because most of the magnetism has been lost. The passage of an electric current along a wire creates a magnetic field around the wire. The fields are in the shape of a series of concentric rings. The more coils used in the electromagnet, the stronger the magnet is. If there is one coil, and another is added, then the two coils have twice the strength of one. This is because the current going through the wire makes the soft-iron core is the factor that induces electromagnetism, as so when there is more current, there will be more wire or or a more magnetised core. Magnets were formed when certain molten metals, (iron, nickel and cobalt,) cool . Normally when the atoms in a non magnetic crystallise, the atoms point in random directions. But because of the properties of the metals mentioned, these atoms line up into parts of the magnetic with similar directions called domains. This is because the earth has a magnetic field, and the atoms in the metal all
Investigating how the velocity of a ball varies with the height of its release on a slope.
Investigating how the velocity of a ball varies with the height of its release on a slope. Safety There are no safety precautions needed besides normal laboratory safety rules. Variables * The gradient of the slope. * The height of the balls release. * The speed of the ball. All other factors will stay the same. * Material of the slope. * The horizontal surface the ball will travel along. * The same ball. * The stopclock used to time the experiment. Preliminary Experiment Apparatus The apparatus I will use is: a plank of wood, a ball, a timer, a ruler and a clamp. Method The apparatus will be set up as above and the ball will be released from various heights and timed from when the ball reaches the bottom of the plank to the end of the ruler. The gradient will be measured using a protractor. Conclusion From the preliminary experiment, the experiment was found to be safe and no other safety precautions will have to be made. The height was best at a maximum of 0.22m because any greater and the ball rolled too fast to measure the time it took. The best angle for the plank was found to be 30o Background Knowledge At position A the ball has Gravitational Potential Energy. Gravitational potential energy = mgh m = mass of the ball (kg) g = the gravitational force (N/kg) h = height (m) As the ball moves from position A to position B it looses Gravitational
The six factors which affect the resistance in wires
The six factors which affect the resistance in wires Resistance Under a potential difference (V) applied across a wire of length (l), there is in the conductor, an electric field (E). In this electric field the free electrons are not however under continuous acceleration (Ee/m). This is because they repeatedly collide with the comparatively massive vibrating atoms losing their kinetic energy. The vibrating atoms having gained this kinetic energy now vibrate more. The resulting increase in the average vibration kinetic energy is rise in temperature. Movement of charge carriers in any medium must necessarily be subject to such collisions causing loss of kinetic energy and generating heat in the medium. This heating of the medium due to the passage of charge carriers is a universal property of all materials and is due to the resistance offered by the material to the flow of charge. The resistance of any material is measured as the potential difference required per unit current in that material. Hence the resistance (R) is quantified as: where (V) is the applied potential difference and (I) the current in the material It should be noted that all materials require to have a potential difference applied in order to maintain an electric current in the material. Thus all materials have resistance. Some materials become more heated than others despite the same rate of flow of
Investigating the Factors That Affect the Resistance of a Wire.
Investigating the Factors That Affect the Resistance of a Wire Resistance occurs when the electrons travelling along the wire collide with the atoms of the wire. These collisions slow down the flow of electrons causing resistance. Resistance is a measure of how hard it is to move the electrons through the wire. There are four main factors that affect the resistance of a wire. These are: * the length of the wire * the width of the wire * the temperature of the wire * the material of the wire Each of these is able to change the resistance. * As the length of the wire increases, the resistance increases. If the length of the wire is increased then the resistance will also increase as the electrons will have a longer distance to travel and so more collisions will occur. Due to this the length increase should be proportional to the resistance increase. * As the temperature of the resistance wire increases, the resistance of the wire increases. This is because if the wire is heated up the atoms in the wire will start to vibrate more because of their increase in energy. This causes more collisions between the electrons. This increase in collisions means that there will be an increase in resistance. * Material of the wire also affects the resistance. The type of material will affect the amount of free electrons which are able to flow through the wire. The conductivity of
My aim for this investigation is to experiment and find out whether the length of a copper wire in a circuit affects the amount of resistance.
GCSE SCIENCE COURSEWORK PHYSICS RESISTANCE OF A WIRE INVESTIGATION BY SAIDUR RAHMAN 1U Aim: My aim for this investigation is to experiment and find out whether the length of a copper wire in a circuit affects the amount of resistance. Factors: The following are factors which affect the resistance of a wire: * Length - this will be the variable in this investigation. The longer the length of the wire, the more resistance there is, resulting in a less current flowing around the circuit. * Thickness - there is more resistance if the wire is thick, because there is a larger diameter, there is more wire overall. This means there is more resistance, resulting in a less current flowing around the circuit. * Temperature - if the wire is hotter, then there is more resistance. This is because there is more energy in the wire. This means the atoms of the metal vibrate more fiercely. This means that the electrons have more difficulty getting through the wire as they collide with atoms which are in their path. This increases the amount of collisions, which means there is more resistance. This results in less current flowing around the circuit. * Voltage - this is obvious, that if there is more voltage, or potential difference, then the less resistance there is. * Material - the type of metal the wire is made of also influences the amount of resistance the wire holds.
Find out how the length and width affect the resistance of a graphite track.
1E GCSE PHYSICS INVESTIGATION PLAN AIM To find out how the length and width affect the resistance of a graphite track. INTRODUCTION In this experiment I will be investigating the electrical resistance of carbon in the form of graphite. Carbon is widely considered to be a conductor; in fact it is the only non-metal conductor. However, physicists think of carbon as a semi conductor. It is a poor conductor at low temperatures, but improves to become reasonable conductor, though not as good as for example copper, silver and gold at room temperature. If one refers to appendix B, the resistively1 chart shows how much more of an efficient conductor gold is in comparison to carbon. This means it is easier for electrons to carry charge through gold than carbon. Carbon has a unique structure, which allows electrical energy to be conducted. There are several types of carbon: carbon 60, graphite and diamond. Carbon exists in these different structures because it has allotropes. Due to its covalent structure carbon can form different allotropes, because of the way the electron orbits join. This applies to carbon in the form of graphite. Carbon in the form of diamond is an electrical insulator. This is because it does not have any loosely held electrons. The structures of carbon look like: However, graphite is bonded in a different way. The electrons orbit in a figure of 8. Electrons
Investigating the factors which affect the flow of electricity
Jenni Fisher 10.1 There are a number of ways in which resistance can be affected, some of which are the length of the wire. This can affect the resistance because if we increase the amount of wire, the current has to travel through more therefore increasing the resistance. Another way in which resistance can be affected is the thickness of the wire. If the wire is very thin, the current wont have as much room to pass through causing it to "struggle" through the wire, therefore causing ore resistance. Changing the metal, can also cause resistance, due to some metals are better conductors of electricity then others. To cause my resistance, I have chosen to change the length of the wire through out the experiment, can also cause resistance, due to some metals being better conductors of electricity then others. To cause my resistance, I have chosen to change the length of the wire through out the experiment. Predictions: In this investigation, I am trying to find out whether or not increasing the wire will cause more or less resistance. I predict that the more we increase the wire the more the resistance will increase, causing the current to decrease. We can say: The shorter the wire the less resistance. The longer the wire the more resistance. Which means if we lengthen the wire less current will pass through. Scientific Knowledge: Resistance is the property of a
Does the length of a wire effect the Resistance?
Science Coursework Does the length of a wire effect the Resistance? I am doing an experiment to test whether the length of a wire affects the Resistance. Resistance is anything in the circuit which slows the flow down. If you increase the resistance less current will flow. My aim is to find out whether resistance is affected when the length of the wire differs. Below is an empty graph of the data I am going to collect. Except I am only going up to 1m, not 1.2m. Background Knowledge Resistance is determined by how good or bad a conductor a material is. Electrons move more easily through some conductors when a potential difference is applied. A good conductor has a low resistance while a poor conductor has a high resistance. The structure of a metal affects the resistance because they have a sea of electrons which allows electrons to pass threw easily, decreasing the resistance. I already know that there are some factors which affect the Resistance in a wire, these include: o Material it's made of o Temperature o Length o Width The material the wires made of would affect the resistance in a wire because as I've already mentioned, Electrons move more easily through good conductors making the resistance lower. Whereas if the wire was not a good conductor electrons would not be able to move around freely, this would then increase the resistance. I know that temperature
An experiment to find the resistivity of nichrome
An experiment to find the resistivity of nichrome A. Planning Plan of the method to be used: - The resistivity of nichrome can be determined using the equation ??=?RA/L Where: R:- Is the resistance of the wire in ?"ohms" and can be determined using the equation R=V/I where "V" is voltage in volts and "I" is current in Amperes. L:- Is the length of the nichrome wire used in metres. A:- Is the cross-sectional area of the wire in metres square and can be determined using the equation A= ??d2 where "d" is the diameter of the wire. If I plot a graph of length on the x-axis against resistance on the y-axis. From the relation R = ? L /A which corresponds to the st. line equation ? y=mx the graph should be a st. line passing through the origin where "m" is the gradient of the st. line graph and corresponds to ?/A. Since the cross-sectional area of the wire can be found by knowing it's diameter. Therefore the resistivity of nichrome can be calculated. ? Diagram of the circuit used in this experiment List of the apparatus used: - - Power pack supply of 4V 2-A variable resistor 3-A full scale deflection ammeter with a measuring range of 0-1 A 4-A digital voltmeter with a measuring range of 0-5 V 5-P, Q represents terminal blocks. 6-Circuit wires 7-PQ=Nichrome wire 8-A meter ruler 9-Michrometer screw-gauge 0-Sellotape Detailed method: - I set up the circuit
