Electric Current — Flashcards

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Electric current is the amount of charge crossing any cross section of a conductor in one second. Formula: I = Q/t. SI unit: ampere (A). 1 Ampere = 1 coulomb/1 Second.

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In an open circuit, electrons move randomly and the net charge crossing any cross section is zero. When a battery is connected, the electric field makes electrons move in one direction, so there is a …

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Use I = Q/t. So Q = I × t = 2 A × 5 s = 10 C. Charge crossing the conductor in 5 s is 10 coulombs.

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An ammeter is used to measure electric current. It is always connected in series to the circuit.

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Drift speed is the constant average speed with which electrons move through a conductor when a battery is connected. It is very small, even though the bulb may glow instantly.

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I = nqAv_d, where n is charge density, q is charge of carrier, A is cross-sectional area, and v_d is drift speed. Also, v_d = I/(nqA).

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The electrons move slowly, but the electric field is set up throughout the conductor instantly when the battery is connected. That field makes electrons move in the specified direction at the same tim…

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Potential difference is the work done by the electric force on unit positive charge to move it from one point to another. Formula: V = W/q = F_e l/q. SI unit: volt. 1 V = 1 J/C.