THEORY:
It was George Simon Ohm (1787-1854) who established experimentally that the current in a metal wire is directly proportional to the potential difference V applied to its two ends, provided that the physical conditions such as temperature remain constant:

I∞V
Exactly how much current flows in a wire depends not only on the voltage, but also on the resistance the wire offers to the flow of electrons. Electrons are showed down because of interactions with the atoms of the wire. The higher the resistance, the less the current for a given voltage V. Resistance is defined as;

Where R is the resistance of a wire or any other device, V is the potential difference across the device and I is the current that flows through it. This result is known as Ohm’s law. In this experiment by using equipment circuit experiment board and resistor, we will experimentally verify the Ohm’s Law.

PROCEDURE:
* I was given a resistor. First of all, I determined the resistance of each resistor from the color codes by using method defined in and wrote my results into the Table. * I constructed the circuit by using circuit experimental board, DC power supply the resistors. * I adjusted the voltage of DC power supply to a suitable value and kept it constant. Also measured the current and the voltage by using the suitable scale and wrote my results into the table. * I choose one of the resistors and connected the circuits given. * Finally I plotted the graph voltages versus current. And calculated the resistance from the graph.

R = 150 Ω
Voltage (v)| Current (mA)|
1.5| 10.16|
5.18| 35.6|
12.59| 86.8|

...Ohms Law
Ohms Law
Thomas More College
Thomas More College
How it applies to different materials
Lucas Cosmidis 11 physics
How it applies to different materials
Lucas Cosmidis 11 physics
Aim/Purpose
The aim is to investigate whether 12v light bulb and a ceramic resistor are either non- ohmic or ohmic. From results calculations can be made to find the resistance produced and then graphed indicating whether the light bulb and ceramic resistor is ohmic or non ohmic
Background Information
An electric circuit is formed when a conductive path is created to allow free electrons to continuously move. This continuous movement of free electrons through the conductors of a circuit is called a current, and it is often referred to in terms of "flow," just like the flow of a liquid through a hollow pipe.
The force motivating electrons to "flow" in a circuit is called voltage. Voltage is a specific measure of potential energy that is always relative between two points. When we speak of a certain amount of voltage being present in a circuit, we are referring to the measurement of how much potential energy exists to move electrons from one particular point in that circuit to another particular point. Without reference to two particular points, the term "voltage" has no meaning.
Free electrons tend to move through conductors with some degree of friction, or opposition to motion. This opposition to motion is more properly...

...Measurement of Resistance and Ohm’sLaw
Section : 04
Instructor’s Name : BERNA DÜNDAR
Experiment Date : 26/02/2014
Submission Date : 05/03/2014
Measurement of Resistance and Ohm’sLaw
Department of Physics,Işık University
Meşrutiyet Köyü,Üniversite Sokağı,No:2 34980 Şile,İstanbul
Abstract
In this experiment we used two multimeters, a set of resistors, a bundle of connecting wires and a DC power supply. By this experiment we learned how to use the electrical instruments, simple circuit elements and we studied Ohm’slaw.
Theory
In electrical circuits, we are concerned with the flow of electrical current around closed loops made up of wires, meters and other components. For this unit we measured and calculated electrical quantities such as direct current, voltage and resistance.
Current
Electrical current is the rate at which electrical charge flows around a circuit. It is measured in units of amperes (A) by ammeters.
Potential Difference (voltage)
Electrical charge tends to move from points of high potential to points of low potential. The difference in potential between two points is called the potential difference or voltage and is measured in units of volts (V).
Resistance
For many devices, it is found that the potential difference appearing across a device is proportional to the current flowing...

...OHM’SLAW
INTRODUCTION
Ohm'slaw states that the current through a conductor between two points is directly proportional to the potential difference or voltage across the two points, and inversely proportional to the resistance between them provided the temperature remains constant.
The mathematical equation that describes this relationship is:
where V is the potential difference measured across the resistance in units of volts; I is the current through the resistance in units of amperes and R is the resistance of the conductor in units of ohms. More specifically, Ohm'slaw states that the R in this relation is constant, independent of the current.
The law was named after the German physicist Georg Ohm, who, in a treatise published in 1827, described measurements of applied voltage and current through simple electrical circuits containing various lengths of wire. He presented a slightly more complex equation than the one above (see History section below) to explain his experimental results. The above equation is the modern form of Ohm'slaw.
In physics, the term Ohm'slaw is also used to refer to various generalizations of the law originally formulated by Ohm. The simplest example of this is:
where J is the current density at a given location in a resistive material, E is the electric field at that...

...energy, as well as dissipating or converting it.
The electrical resistance per unit length, area, or volume of a substance is known as resistivity. Resistivity figures are often specified for copper and aluminum wire, in ohms per kilometer.
Opposition to AC, but not to DC, is a property known as reactance. In an AC circuit, the resistance and reactance combine vectorially to yield impedance.
Ohm'sLaw is the mathematical relationship among electric current, resistance, and voltage. The principle is named after the German scientist Georg Simon Ohm.
In direct-current (DC) circuits, Ohm'sLaw is simple and linear. Suppose a resistance having a value of R ohms carries a current of I amperes. Then the voltage across the resistor is equal to the product IR. There are two corollaries. If a DC power source providing E volts is placed across a resistance of R ohms, then the current through the resistance is equal toE/R amperes. Also, in a DC circuit, if E volts appear across a component that carries Iamperes, then the resistance of that component is equal to E/I ohms.
Mathematically, Ohm'sLaw for DC circuits can be stated as three equations:
E = IR
I = E/R
R = E/I
When making calculations, compatible units must be used. If the units are other than ohms (for resistance), amperes (for current), and volts for voltage), then unit conversions should be made before calculations are done. For...

...JOULE’S LAW
Introduction and research question
In this experiment, we were going to investigate the resistance R of an immersion heater. We had to make our own heater, and measure the resistance using a multimeter. Then we had to measure the current I, using an ammeter and a voltmeter. And at last, we had to determine the power P of the immersion heater. This experiment would require to make a table with the data collection, a graph, and a few calculations using Joule’s and Ohms law.
Our research question is: How can we prove Joule’s law?
Experiment procedure
First build an immersion heater with a cable joints and wires. The heater consists of an approximately 25 cm twisted kanthal wire. Wrap the wire around a pencil for a slinky effect. Tighten the screws to assure that the wires are fastened. To determine the power P of the immersion heater, fill up half of a plastic cup with regular tap water (must be able to cover the wire), and heat it with your immersion heater. By measuring the temperature of water as a function of time, and draw a graph, you can calculate the power P. The heater is lowered into the water and is connected to an AC power supply (alternating current). At the same time using an ammeter and voltmeter, measure the current I through the resistor and the pad. Measure for 5 – 10 min. Make a table and a graph.
Apparatus
Data collection
Our first investigation was to measure the resistance of the immersion...

...CONFIRMING OHM’SLAW
BY ALEX KUCHMENKO
9.1
Aim – To Confirm Ohm’sLaw through experimentation.
Hypothesis – The More Ohms the resistor has, the weaker the current will become.
Materials – Power pack, ammeter, voltmeter, resistors, connecting wires.
METHOD –
1. POWER PACK
POWER PACK
RESISTOR
RESISTOR
VOLTMETER
VOLTMETER
AMMETER
AMMETER
A
A
V
V
Set up a known resistor in a simple circuit.
2. Vary the voltage and record the potential drop (V) and the current (I) through the resistor. Do this for a number of settings on the power pack, for example do two, four and six volt settings. (Remember the power pack should only be turned on while doing readings.)
2. Vary the voltage and record the potential drop (V) and the current (I) through the resistor. Do this for a number of settings on the power pack, for example do two, four and six volt settings. (Remember the power pack should only be turned on while doing readings.)
Another experiment to perform is to attach several resistors to the circuit, for example a 2.2Ω and a 10Ω would make a 12.2Ω resistor.
4. Construct a line graph of the data in the previous table. Put all three sets of data on the same table.
DISCUSSION –
The calculated unknown resistances and line graph confirmed...

...Conclusion
Ohm'sLaw states that V=RI where V is the difference of potential at the poles of the element (measured in volts), R is the resistance of the element being tested (a resistor in this case, measured in ohms), and I is the current passing through the circuit (measured in milliamps). When the Y-intercept on the attached voltage drop vs. current in the conductor graph is examined, it is observed that the the ranges of R values overlap, also the expected y-intercept value of 0 falls between the maximum and minimum deviation. By further examining the graph,it is possible to notice that the plot of the voltage drop across the conductor versus the current in the conductor results in a straight line. Furthermore, the origin (0,0) is within experimental error for the y-intercept of the graph. Both these statements show that the tested resistor verified Ohm'sLaw since theoretically the y-intercept should be 0 and the voltage drop across the conductor versus the current in the conductor should be directy proportional. This can be concluded by observing the equation which is y = .054492x ± 0.0016x -.0254 ± 0.10.
This laboratory had few causes of error that could significantly affect results. The most important factor was a mildly fluctuating power supply (the indicated current did not remain perfectly stable after being adjusted). Another possible cause of error is the possibility of misreading the voltage drop...

...New York City College of Technology
Ohm’slaw & resistors in parallel & in series
Lab 4
Class: PHY 1434-E475
Due date: March, 13 20144
Group Names: Hisham Sageer
Objectives:
Our object is to confirm Ohm’slaw by analyzing the dependence of the electrical current as a function of voltage and as a function of resistance. Also, we studied the current flow and voltage in series and parallel. Finally, the lab determined the equivalence resistance of series and parallel combination of resistors and compared the results with theoretical data.
Theoretical Background:
The first thing that needs to be described in this lab is what the electric current I:
I =. The electric current is defined as charge over time and the unit is ampere (A). In a case where we have the voltage, resistance and current we can set the equation for resistance to be; R = where the unit is called Ohm (Ω). “The current through a resistor is directly proportional to the applied voltage V and inversely proportional to the resistance” (College Physics Laboratory Experiments, 43) in our lab experiment we used some machinery to produce and to measure voltage and some current. We were then able to find its resistance. These apparatus are called ammeter which displays the amount of current in circuit, and the voltmeter to read the voltage (potential difference). Reminding that this diagram is named circuit and V...