Unit 2.1- Conduction Of Electricity

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    • Current flows around any circuit where there is a potential difference.
    • Current: Rate of flow of charge
    • Electrons: negatively charged particles that can move in metals
    • Current: The flow of electrons
    • Electrons flow from the negative to the positive terminal in a circuit.
    • Ammeters measure the current flowing through a circuit/component.
    • Ammeters are connected in series to measure the current of a circuit.
    • I = ΔQ / Δt
    • Current moves in the opposite direction to the electrons.
    • Current moves from the positive to the negative terminal.
    • The unit of current is Amperes (A).
    • The total current entering a junction is equal to the total current leaving a junction.
    • Kirchhoff's first law: The total charge of a circuit is always conserved.
    • Mean drift velocity: the average distance travelled by an per unit time.
    • Electrons move randomly when no potential difference is applied to a wire.
    • Electrons move in the positive direction when a potential difference is applied to a wire.
    • The more electrons a wire has, the more current it can carry.
    • The more electrons a wire has, the more resistance it can also have.
    • Conductors have high electron densities of around 10²⁹.
    • Semiconductors have electron densities of around 10¹⁹.
    • Insulators have low electron densities of around 10⁹.
    • Potential difference = Voltage
    • Potential difference: The work done in the circuit per unit of charge.
    • Potential difference is measured in Volts (V).
    • Potential difference of a circuit or component is measured by connecting a voltmeter in parallel.
    • V = W / Q
    • Electromotive force: total voltage produced by a cell, but not all of it may reach the circuit.
    • Electromotive force (EMF) is measured in Volts (V).
    • EMF = (r + R) * I
    • EMF is always greater than the voltage of a circuit.
    • Resistance: The opposition to the flow of electrons in a circuit.
    • Ohm's law: The current is directly proportional to the potential difference.
    • R = V / I
    • As the current increases, the resistance decreases.
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