Electric Current Through Conductors

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Electric current is defined as the amount of charge flowing through a cross-section per unit time. I = q/t. The SI unit is ampere (A). 1 ampere = 1 coulomb/second. Current can range from nanoamperes (…

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By convention, the direction of current is taken as the direction in which positive charges would move, even though in metallic conductors, it is actually electrons (negative charges) that move in the…

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Drift velocity (Vd) is the average velocity with which free electrons move in a conductor under the influence of an electric field. Derivation: For a conductor with length L, cross-sectional area A, a…

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Given: D = 0.02m, r = 0.01m, n = 10²⁸ electrons/m³, I = 100A, e = 1.6 × 10⁻¹⁹ C Solution: A = πr² = 3.142 × (0.01)² = 3.142 × 10⁻⁴ m² Vd = I/(nAe) = 100/(3.142 × 10⁻⁴ × 10²⁸ × 1.6 × 10⁻¹⁹) = 100/(5.02…

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Ohm's law states: 'The current through a conductor is directly proportional to the potential difference applied across its ends, provided the physical state of the conductor remains unchanged.' Mathem…

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Resistance (R) is the opposition offered by a conductor to the flow of current. R = V/I. Unit: ohm (Ω). 1Ω = 1V/1A. Conductance (C) is the reciprocal of resistance. C = 1/R. Unit: siemens (S) or (Ω)⁻¹…

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Given: Total voltage V = 2 × 1.5V = 3.0V, Current I = 0.5A Solution: Using Ohm's law, R = V/I = 3.0V/0.5A = 6.0Ω Therefore, resistance of the glowing filament = 6.0Ω…

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For an electron in electric field E: Force F = eE, acceleration a = eE/m. If τ is average time between collisions, drift velocity Vd = aτ = (eEτ/m). From Vd = J/(ne), we get J/(ne) = (eEτ/m), which gi…