Aim:
To determine the relationship between the length of eureka wire, and resistivity of the wire. Hypothesis:
As the length of the wire increases, the resistance of the wire will increase. Background:
Some materials have consistent resistance at the same temperature regardless of how much voltage is applied through them, these materials are known as ‘Ohmic’ resistors. This is because they are said to obey Ohm’s law, which states that if a voltmetre is used to measure the voltage (V) of an unknown resistance (R), and an ammetre is used to measure the current (i) through the same unknown resistance, then ‘R’ would be given by R = V/i . The eureka wire used in this experiment is an ohmic resistor, so theoretically it can be used to measure the relationship between its length and resistance without other variables affecting it. Equipment:

1. 1 metre length of eureka wire
2. Power supply unit
3. 1 Voltmetre
4. 1 Ammetre
5. 1 Rheostat
6. Connecting wires
Procedure:
1. Measure and cut 1 metre of wire
2. Set up the electrical circuit as in the diagram
3. Set the rheostat at its furthest point on one end.
4. Connect the wire into the circuit at 10cm length
5. Turn the power supply on, and record the voltage and amp readings. Turn the power supply off immediately after to prevent temperature build up in the circuit. 6. Repeat step 5 twice, adjusting the rheostat to the middle position, and then the other end position. 7. Repeat steps 3-6 increasing the length of the wire 10cm at a time, up to 1 metre total length 8. Divide the voltage by the amp readings to calculate the resistance 9. Plot the wire length against the resistance

Diagram:

Results: Table showing the calculated resistance of the wire Wire Length (cm)| Resistance 1(Ω)| Resistance 2(Ω)| Resistance 3(Ω)| Average Resistance(Ω)| 100| 3| 2.9| 2.7| 2.87|
90| 2.8| 2.5| 2.2| 2.5|
80| 2.5| 2.4| 2.6| 2.5|
70| 2.2| 1.9|...

...time) through a conducting or semiconducting medium for a given resistance to the flow. Voltage is symbolized by an uppercase italic letter V or E. The standard unit is the volt, symbolized by a non-italic uppercase letter V. One volt will drive one coulomb (6.24 x 1018) charge carriers, such as electrons, through a resistance of oneohm in one second.
Voltage can be direct or alternating. A direct voltage maintains the same polarity at all times. In an alternating voltage, the polarity reverses direction periodically. The number of complete cycles per second is the frequency, which is measured in hertz (one cycle per second), kilohertz, megahertz, gigahertz, or terahertz. An example of direct voltage is the potential difference between the terminals of an electrochemical cell. Alternating voltage exists between the terminals of a common utility outlet.
A voltage produces an electrostatic field, even if no charge carriers move (that is, no currentflows). As the voltage increases between two points separated by a specific distance, the electrostatic field becomes more intense. As the separation increases between two points having a given voltage with respect to each other, the electrostatic flux density diminishes in the region between them.
Resistance is the opposition that a substance offers to the flow of electric current. It is represented by the uppercase letter R. The standard unit of resistance is the...

...Investigating Ohm’s Law
Introduction/Background
Current is the rate of the flow of energy; an electric current is the flow of electrical charge around the circuit. It is measured in ohms (Ω). The quantity of flow in an electric circuit is dependent on the ohmic value of the resistance. The amount of resistance in a given circuit is stationary and is not dependent on the current. “The higher the voltage of a battery, the more potential energy per coulomb of charge it can supply.” (1)
It is observed (in an ideal circuit), that when all other elements maintain at a constant level, an increase in voltage will definitely mean an increase in the flow of electrons (current). As voltage increases, so does current so they have a positive relation to each other (Figure 1a.). In a non-theoretical circuit the light bulbs and wires increase the resistance as the current flows through the circuit, weakening the current itself (Figure 1b.).
However there is another variable observed, in the form of resistance. Resistance is the force acting against current; it impedes the flow of current. It is observed that, as more globes are added in a circuit the weaker the current flow. Therefore it can be deduced that as the resistance increases, the current decreases, this is an inverse relationship between the two variables. Materials with low resistance (e.g....

...Study about Ohm's Law:
• To verify Ohm’s Law by calculating voltage, current and resistance based on different views of Ohm’s law as well as measuring those values to compare the theoretical results with the actual results.
• To verify the relationships of R-I, V-I and R-V given ohm’s law by increasing one parameter while holding the other parameter constant, then measuring and calculating equivalent results of the third parameter.
What is Ohm's Law:
Ohm's Law is made from 3 mathematical equations that shows the relationship between electric voltage, current and resistance.
What is voltage? An anology would be a huge water tank filled with thousands of gallons of water high on a hill.
The difference between the pressure of water in the tank and the water that comes out of a pipe connected at the bottom leading to a faucet is determined by the size of the pipe and the size of the outlet of the faucet. This difference of pressure between the two can be thought of as potential Voltage.
What is current? An analogy would be the amount of flow determined by the pressure (voltage) of the water thru the pipes leading to a faucet. The term current refers to the quantity, volume or intensity of electrical flow, as opposed to voltage, which refers to the force or "pressure" causing the current flow.
What is resistance? An analogy would be the...

...CONFIRMING OHM’S LAW
BY ALEX KUCHMENKO
9.1
Aim – To Confirm Ohm’s Law 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...

...OhmsLawOhmsLaw
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...

...Name: _____________________
Wire Resistance and Ohm’s Law PhET MiniLab
Introduction: When an electrical potential exists in a circuit, a current may flow. Current is the flow of electrons in a circuit. Resistance in the circuit slows the flow of the electrons, reducing the current in the circuit. We will use the mathematical form of Ohm’s Law frequently when we investigate electric current and circuits later in this unit.
• Open the PhET Simulation Electricity, Magnets, and Circuits ( Resistance in a Wire[pic]
As wire length (cm) increases, the resistance (Ω) _________________
As wire area (cm2) increases, the resistance (Ω) __________________
As wire density (Ωcm) increases, the resistance (Ω) _______________
Procedure: Ohm’s Law: Electricity, Magnets, and Circuits ( Ohm’s Law [pic]
mA is milliamps, and _________ milliamps equals one Ampere.
• Move the potential (volts) and resistance (ohms) sliders and observe the current (amps)
As voltage increases, current __________________.
As resistance increases, current ________________.
Fill out the tables below and check your work in the simulation. ( ½ pt each )
• Remember, the simulation shows milliamps.
• You should show Amperes
V = I * R
|8.0 V |A |800 Ω...

...New York City College of Technology
Ohm’s law & 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’s law 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...

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