Electricity — Flashcards

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Electric current is the rate of flow of electric charges through a conductor. Mathematically, I = Q/t, where I is current (amperes), Q is charge (coulombs), and t is time (seconds). The SI unit is amp…

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Electric current was defined before electrons were discovered. Scientists assumed positive charges were flowing, so they defined current direction as the flow of positive charges. Since electrons (neg…

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Potential difference between two points is the work done to move a unit positive charge from one point to another. V = W/Q, where V is potential difference, W is work done, and Q is charge. SI unit is…

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Ohm's Law states that the potential difference across a conductor is directly proportional to the current flowing through it, provided temperature remains constant. V ∝ I, or V = IR, where R is resist…

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Resistance is the property of a conductor to oppose the flow of electric current. It is the ratio of potential difference to current: R = V/I. SI unit is ohm (Ω). 1 Ω = 1 V/A.

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Resistance depends on: (1) Length (l) - R ∝ l (2) Area of cross-section (A) - R ∝ 1/A (3) Nature of material (resistivity ρ). Combined formula: R = ρl/A, where ρ is resistivity.

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Resistivity (ρ) is the resistance offered by a unit cube of material. It is a characteristic property of the material. From R = ρl/A, we get ρ = RA/l. SI unit is ohm-meter (Ω m).

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Given: Q = 300 C, t = 5 min = 300 s Using I = Q/t I = 300 C / 300 s = 1 A Therefore, current = 1 ampere…