# Incandescent Light Bulb and Wire Resistance

Topics: Incandescent light bulb, Ampere, Electric current Pages: 2 (279 words) Published: October 12, 2013
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 ___1000______ 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___________. 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.1A800 Ω
2.0 V.044 A450Ω
.2V.0058 A430 Ω
6.9V.069 A100 Ω
6.4 V.0213A300 Ω

Conclusion Questions: ( ½ pt each)
1.Incandescent light bulbs have a very thin filament that glows when hot. Thin filaments have very high / low resistance. 2.The 12V battery in your car operates a 25 amp car stereo. What is the resistance of this stereo system? __.48 ohms_________ 3.A “2D” Maglite flashlight runs on 3.0V. What is the current through the bulb if resistance is 15 Ω ? _.2 amps___________ 4.How many volts must an iPod charger provide to charge an iPOD using .85 Amps at 35 Ω? _29.75 volts____________ 5.You need to buy a long extension cord to power a stereo at your spring break BBQ. You need 200feet. You have a 50 ft cord that will work. You rationalize that four such 50 ft cords will do the job. Is this a good idea? Why or Why not? ___________________________________________________________________________________________...