Name __________________________Wire Resistance and Ohm’s Law

Go to http://phet.colorado.edu/simulations/sims.php?sim=Ohms_Law and click on Run Now.

Wire Resistance and Ohm’s Law

Procedure Part I Wire Resistance:
open the PhET Simulation Electricity, Magnets, and Circuits ( Resistance in a Wire. As wire length (cm) increases, the resistance (Ω) _increases________ As wire area (cm2) increases, the resistance (Ω) _decreases_________ As wire resistivity (Ωcm) increases, the resistance (Ω) _increases____ Procedure Part II: Ohm’s Law: Electricity, Magnets, and Circuits ( Ohm’s Law mA is milliamps, and _1,000_____ milliamps equals one Ampere. • Move the potential (volts) and resistance (ohms) sliders and observe the current (amps) As voltage increases, current _increases__________.

As resistance increases, current _decreases (slows)__.
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 |.01 A |800 Ω | |2.0 V |.044 A |450 Ω | |0.2 V |.0058 A |430 Ω | |6.9 V |.069 A |100 Ω | |6.4 V |.0213 A |300 Ω |

Conclusion Questions: ( ½ pt each)
1. Incandescent light bulbs have a very thin filament that glows when hot. Thin filaments have very / low resistance. 2. The 12V battery in your car operates a 25 amp car stereo. What is the resistance of this stereo system? _0.48 Ω ___ 3. A “2D” Maglite flashlight runs on 3.0V. What is the current through the bulb if resistance is 15 Ω ? _.20 amps____ 4. How many volts must an iPod charger provide to charge an iPOD using .85 Amps at 35 Ω? _29.75 V__________ 5. You need to buy a long extension cord to power a stereo at your spring...

...LAB 01
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...

...Introduction
The resistance of a wire depends on certain factors. Some of these variables are listed below:
Length of wire
Diameter or thickness of wire
Temperature at which wire is kept
The material of which wire is made out of.
The potential difference or voltage.
Humidity
Cross sectional area.
Voltage across circuit
All these factors will have to be kept constant except...

...investigate how the resistance of a wire is affected by the length of the wire.
Theory
What is resistance?
Resistance is a force which opposes the flow of an electric current around a circuit so that energy is required to push the charged particles around the circuit. The circuit itself can resist the flow of particles if the wires are either very thin or very long.
e.g. The filament across an electric...

...METHOD
 Set p the equipment as shown on the diagram.
 One meter length of wire is fixed to a one meter ruler.
 The first crocodile clip is clipped to the wire at the 0cm position on the one meter ruler.
 The second crocodile clip is clipped to the 10cm position.
 The power supply is turned on. The voltage and current are then read of the ammeter and voltmeter, and recorded.
 The power supply is then turned off...

...The problem with using resistance as a measurement is that it depends not only on the material out of which the wire is made, but also the geometry of the wire. If we were to increase the length of wire, for example, the measured resistance would increase. Also, if we were to decrease the diameter of the wire, the measured resistance would increase. We want to define a property that describes a...

...that affect the resistance of a piece of wire; the one I am investing is the length at constant temperature.
My objective in this experiment is to investigate one of the factors that affect the resistance of a piece of wire. The factor I chose was length.
Factors:
There our four different things that affect the resistance of a wire:
1. The Length because the wire is thinner than the...

...measurement of the wire or a temperature rise. The two results for 100cm are exactly the same, and it is near to the manufacture's line, so this is the most accurate point.
The other three readings have almost the same inaccuracy, an average of 10%, which again, is fairly accurate. The inaccuracy could have been because of the wire coming from a different manufacturer to the predicted results, as there is some discrepancy between the amount of copper and nickel...