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View Vow How many electrons go past a point every second in a wire if the current is 12 Amps?

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Objectives Understand that current tells us how much charge (think moving electrons! – but more to come on this) moves past a certain point every second. We all know “Resistance is futile”…but what is resistance when we are talking about Current?

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Homework Castle Learning – Current and Resistance

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Test Corrections today post and tomorrow. I do have a meeting today but I will be in here so feel free to come today for corrections. Please look over, ask questions, check the scoring and then return to your mailbox.

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Worksheet Current

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4.2.2 Electrical Resistance Electrical Stopping Power

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Definitions resistance: OPPOSITION TO CURRENT unit: Ω factors that change resistance: resistivity: MATERIAL length cross-sectional area temperature

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R A Resistance Factors R ρ R L R Temp. NEXT

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R A Resistance Factors R ρ R L R Temp. To build an “ideal” conductor with the smallest possible resistance you would select one that is: LOW RESISTIVITY, SHORT, WIDE, COLD

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Determine the resistance of a 1.0 meter long copper wire with a cross-sectional area of 0.01 meter 2. Example #1 R = ρL / A R = (1.72 x 10 -8 Ω·m)(1.0 m) / (0.01 m 2 ) R = 1.72 x 10 -6 Ω

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A piece of wire that has a length of 5.0 x 10 7 meters and a cross-sectional area of 0.025 meter 2 has a resistance of 31.8 ohms. –What is the composition of this wire? Example #2 R = ρL / A ρ = RA / L ρ = (31.8 Ω)(0.025 m 2 ) / (5.0 x 10 7 m) ρ = 1.59 x 10 -8 Ω·m

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End of 4.2.2 - PRACTICE

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Electric Current Flow of electric charges through a piece of material Amount of flow depends on material and the potential difference across the material.

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