What factors affect the resistance of wire? Aim: my main aim is to investigate the factors that affect the resistance in a conductor, in which here I am using a nichrome wire. The focal factors that affect the resistance in a conductor are: Length Temperature Cross- section area Material Hypothesis: I think that the more the cross-section area, the lower the resistance in the conductor or the nichrome wire will be. This is because the resistance happen due to the movement of the electrons through the material ( once a voltage has been applied ) they collide with the atoms in the material and as a result lose some of their energy.
The idea of resistance is simply how difficult it is for the electrons to move through a material. The more difficult it is, the more energy they lose in the material on their movements. The definition of an electrical resistance is the ratio of voltage to current. The equation we use to find the resistance from the current and voltage is: Resistance (R) = Voltage (V) / Current (I) To put it in a simpler way, it is the number of volts difference across the object when one amp of current flows.
It should be remembered that voltage is the number of joules of energy transferred by one coulomb of charge, and that current is the number of coulombs of charge passing a place each second. Now what the object is made of this means its resistance will have an affect on its resistance. Not all metals are equally as good at conducting electricity. A longer length of wire will also make it difficult for the current to flow, as there is more material to travel through. The temperature too plays a great role in the affect of the metallic conductor’s resistance.
A hot metal has a larger resistance than a cooler one; therefore the temperatures are adjusted to a lot higher value to get a decent change in the resistance. What we know about current already is that it is nothing but the rate of flow; however when the temperature rises the atoms also vibrate in their own balance more forcefully impending the flow of electric charges due to more frequent collisions. More electrons are available to conduct the current in the wire. Collision with lattice ions is less frequent.
The current increases and the resistance decreases. However, the cross-section area will also have an effect, as the larger this is, the more charge can pass through it at the same time as it passes through a given length. Therefore, a larger area of cross-section in fact reduces the resistance. The cross-section area has a continuous variable, i. e. one that is measured and can have any value. One can put your results onto a point graph and get a significant conclusion. That is why I have chosen to change the cross-section are of the nichrome wire.
Introduction: The reason of my investigation is to discover the factors responsible for affecting the resistance of a wire in an electrical circuit. Many factors will have to be investigated prior to the experiment. Prior information of electrical circuits and the factors of resistance will be necessary. The definite objective will be the study on the subject matter which is proven by experimentation. Resistance: Resistance is when electricity is concerned, is the ability of a substance to resist the flow of electricity through it.
Good conductors are related with low resistance and poor conductors are related with high resistance. As resistance is responsible for the current that flows, a high resistance will be responsible for a low current and a low resistance will be responsible for a higher current. This is definition of resistance given by Hutchinson’s Encyclopedia: ” In physics, property of a conductor that restricts the flow of electricity through it, associated with the conversion of electricity energy to heat; also the magnitude of this property.
Resistance depends on many factors, such as the nature of the material, its temperature, dimensions, and thermal properties; degree of impurity; the nature and state of illumination of the surface; and the frequency and magnitude of the current. The SI unit of resistance is the ohm (? ). Resistors are devices, as a coil or length of wire, used in a circuit primarily to provide resistance” Resistors: In physics any component in an electrical circuit used to introduce resistance to a current. Resistors are often made from wire-wound coils or pieces of carbon.
Rheostats and potentiometers are variable resistors. Ohms Law: Ohms Law is defined as; “provided that the temperature remains constant, the ratio of potential difference (p. d. ) across the ends of a conductor (R) to the current (I) flowing in that conductor will also be constant. ” Or… the current passing through a wire at constant temperature is proportional to the potential difference between its ends. From this, we conclude that: voltage divided by resistance ( I=V/R ), resistance equals voltage divided by current ( R=V/I ), and voltage equals current times resistance ( V=IR ).
The important factors here are the temperature. If calculations based on ohms law are produced accurate results must remain constant. And if precautions are taken there will be no significant threat to the accuracy of the results. Factors affecting the resistance of a wire at constant temperature. Resistance in different sized conductors A thicker wire offers less resistance to current than a thinner one of the same material. This is because current consists of electrons flowing through the metal of the wire. The electrons skip from atom to atom in the metal in retort to the electric field in the circuit.
A conductor with a larger cross-section allows more electrons to relate with the field. Because there is more current with a given voltage, a conductor with a larger cross-section has lower resistance. The resistance of a wire is inversely proportional to its cross-section width. The area/cross-section of the wire is double, the resistance will be halved. Length of the wire is also a factor in resistance. If the length of the wire doubles, the resistance is doubled. This is because twice the length of wire is equal to two identical resistances in series.
Resistances are just added together in a series circuit so having a long length of wire will just be the same as having two lengths of half the size, etc… Resistance will increase with length. Therefore I can say that Resistance is proportional to length. Effect of temperature on a conductor ( Nichrome Wire ) We already know that heat in metals increases resistance somewhat. And this will produces more vibration which makes the atoms get in the way of the electrons more frequently. The electrons then must spend extra time on flawed path instead of going straight ahead.
This cuts down the current slightly. In the recent theory, the atoms spread the electron waves carried by the electrons. Current can sometimes cause the wire to get hot; this would increase the resistance. Different Materials: Different materials have different resistances. That is why metals have precise reasons in electrical circuits. Copper is mainly used in electrical circuits because of its low resistance. It is energy capable and is second only to silver, which is too expensive for general use. Materials with high resistances have their purposes in some electrical circuits too.
Nichrome, an alloy of 80% Nickel and 20% Chromium is often used as a heating aspect in electrical devises. The difference in resistivity in materials are caused by the number of free electrons that the material has. If there are more free electrons, less energy is needed to be spent. There is no way that this can be calculated with the available level of equipment other than experimentation. The other reasons in concern such as impurities in the wire, thermal properties and the state of illumination at the surface will be unimportant in this study because there is no possible way they can be taken into account.