Ohm's Law Aim:To prove ohms' law, and to study the relationship between current and potential difference (voltage). Hypothesis: The current flowing through a metal wire is proportional to the potential difference across it (providing the temperature is constant). Apparatus: 1. Power Supply 2. Variable resistor 3. Ammeter 4. Voltmeter 5. Resistors 6. Electric wires Diagrams: ========= R1: R2: R1 + R2 (in series): R1 + R2 (in parallel): Method: 1. Set
resistance), I=V/R or current equals voltage over resistance. This is known as Ohm’s Law. Electrical resistance is calculated by the formula, R=V/I or resistance equals voltage over current. Ohm’s law however does not hold true if temperature changes. Materials that obey Ohm’s law are known as ohmic or linear because the potential difference across it varies linearly with the current. In addition, whether or not a material obeys Ohm’s law its resistance can be described in bulk resistivity. Furthermore, over
needed to know what an ohmic resistor was. OHM'S LAW The current flowing through a metallic conductor is proportional to the potential difference. This is only true when the temperature is constant. If you read the current as you change the potential difference across a conductor the ratio V/I (volts over amps) is the same if it is ohmic. From digitalbrain.com --------------------- An ohmic resistor is a component in which Ohm's law is satisfied. [IMAGE][IMAGE][IMAGE][IMAGE][IMAGE]
V doubles I etc. Such conductors obey Ohm's Law, stated as follows: The current through a metallic conductor is directly proportional to the voltage across its ends if the temperature and other conditions are constant. These are called ohmic or liner conductors and since I V, it follows that V / I = constant. The resistance of an ohmic conductor therefore does not change when the voltage does. Overall, my experiment obeyed Ohm's law. However, my results may have been effected
Mathematically Treated). This was a mathematical description of conduction in circuits modeled after Fourier's study of heat conduction. This is also known as Ohm's Law. Ohm's Law, which is Georg's greatest accomplishment, started as an experiment. The experiment's purpose was to find the relationship between current and the length of the wire carrying it. Ohm's results proved that as the wire increased the current decreased. Ohm came up with a formula to state these findings. It is V=IR, where as V=Voltage
taught him basic practical skills. While still young, Ohm's ambition was to become a scientist and to work at one of the great German Universities. He studied at the University of Erlangen, and at the age of 24 (1813), he began teaching physics and mathematics at the Realschule in Bamberg. He remained there for almost four years, before becoming a professor of mathematics for the Jesuit's college at Cologne in 1817. [IMAGE] Ohm's main interest was current electricity. Ohm made only
circuit (in series) and the voltage across the wire (in parallel). These measurements are then applied to this formula: V = I ´ R where V = Voltage, I = Current and R = Resistance This can be rearranged to: R = V I Ohm’s Law It is also relevant to know of Ohm’s Law, which states that the current through a metallic conductor (e.g. wire) at a constant temperature is proportional to the potential difference (voltage). Therefore V ¸ I is constant. This means that the resistance of a metallic
Therefore if you double the voltage, I think the current will also double. This is similar to doubling the pressure in the water pipe, which in affect, will double the flow of the water. The reason I will test my theory is so I can see if ohm's law was correct by saying, "Voltage is proportional to current." This is one of the main reasons that I think doubling the voltage will cause the current to double. Resistance is the force that acts against current. Fair Test To make
Factors Affecting the Resistance of a Wire The aim of this experiment is to investigate one factor that affect the resistance of a wire. I will do this by performing an experiment. First I will need to identify the factors that effect resistance. There are a few factors that affect the resistance, it is determined by the properties an object has. This is know as resistivity. The factors I can investigate are : Ÿ Temperature Ÿ Length Ÿ Cross-sectional area/width Ÿ Material
why it occurs, what causes it, and how it can be used to our advantages. Resistance is a term used to describe the property that various materials possess to restrict or inhibit the flow of electricity. Whether or not a material obeys Ohm's law, its resistance can be described in terms of its resistivity. The electrical resistance of a wire would be expected to be greater for a longer wire, less for a wire of larger cross sectional area, and would be expected to depend upon the material
(in series) and the voltage across the wire (in parallel). These measurements are then applied to this formula: V = I ´ R where V = Voltage, I = Current and R = Resistance This can be rearranged to: R = V I Ohm's Law It is also relevant to know of Ohm's Law, which states that the current through a metallic conductor (e.g. wire) at a constant temperature is proportional to the potential difference (voltage). Therefore V ¸ I is constant. This means that the resistance of a metallic
it predominates, although it is a characteristic of every part of a circuit, including connecting wires and electric transmission lines. In circuits where the current (I) and voltage (V) are related by a simple proportionality constant, as in OHM'S LAW, V = RI, the proportionality constant R is the resistance of the circuit. This discovery was made by Georg Simon Ohm (1787-1854), a German physicist, therefore, Ohm is the common unit of electrical resistance. Resistance is the property
circuit, this can be in the form of ions in a liquid or electrons in a metal. Resistance is anything that slows the flow of electrons round the circuit. Ohm's law states that the voltage is equal to the current multiplied by the resistance - V=IR This can be re-arranged to say R=V/I. Ohms law states that in a metal component the ratio of voltage to current remain constant, meaning that the resistance stays the same as long as the temperature remains the
The Resistance of a Wire Introduction In this investigation I will be trying to find out the resistance of a piece of constantan wire. I know that according to ohms law, the p.d is proportional to the current so if the p.d doubles so will the current. Through past experiments I know how to work out resistance, to work it out I use this formula Where the resistance is R, the p.d is V and the current is C, from this you can work out the resistance of any circuit. Aim of the Preliminary
difference (voltage) between the ends of conductor is increased the current passing through it increases. If the temperature of the conductor doesn't change, the current that flows is proportional to the voltage applied. This is called Ohms Law. Ohms Law= Potential Difference x Current or Potential Difference = resistance x current or The unit of resistance is measured in Ohms (W). Measuring Resistance The voltage across the resistor is measured using the voltmeter. The current
Measuring the Resistivity of a Wire Aim The aim of this experiment is to find out how the area of the cross section of the wire affects the resistance and also to find out the resistivity of the wire having found the resistance over a certain length and using a certain cross sectional area. I will also experiment to see how the length of the wire affects the resistance. Plan The first thing that I will do is to set up the apparatus as shown below. A,V Except for the experiment
investigation to show how the voltage affects the current flowing through a light bulb. Hypothesis:~ I predict that as the current increases the voltage of the lamp will also increase; thus causing the resitance to decrease. I think this because of Ohm's Law which states that current will increase in proportion to voltage; if the current is doubled the voltage is also doubled. Bearing this in mind my graph should resemble my diagram below: [IMAGE] X X X X [IMAGE] X X X
the resistance of a wire. Background Information Although current and potential difference measure different things, they are related to each other. In 1826, Georg Ohm discovered that doubling the p.d. doubled the current. (Taken from Ohm's Law: the current flowing through a metal wire is proportional to the potential difference across it (providing the temperature is constant). Electricity flows through a conductor, in this case the wire, by means of free electrons. The number of
Resistance is an opposition to the flow of electrons. It is the potential difference divided by the current. How is resistance measured? =========================== Resistance is measured in ohms (W) using an ohmmeter ( W ). Ohms Law ======== Resistance is worked out using the following scientific model (Reference from Roger Muncaster's A level Physics): r = resistivity (Wm) l = length (cm) A = Cross sectional area (cm ) K = Constant R=rl A If r and A are
Resistance in a Wire Introduction: ============= 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 'jumps' atoms. So if we double the length of a wire, the number of atoms in the wire doubles, so the number of jumps double, so twice the amount of energy