Electricity: Electric Charge and Current

Study Notes

Electric potential, or voltage, is the potential difference between two points
It is measured in volts (V)
Voltage is the "pressure" that drives electric current
Electric potential energy is converted to kinetic energy as charge flows through a circuit

Resistance is the opposition to the flow of electric charge
It is measured in ohms (Ω)
Resistance depends on the material, length, and cross-sectional area of a conductor
Ohm's law: R = V/I, where R is resistance, V is voltage, and I is current

Electric circuits consist of conductors, resistors, and sources of voltage
Series circuits: components are connected one after the other, and the current is the same throughout
Parallel circuits: components are connected between the same two points, and the voltage is the same throughout
Kirchhoff's laws:
- Junction rule: the sum of currents entering a junction is equal to the sum of currents leaving a junction
- Loop rule: the sum of voltage changes around a closed loop is zero

Electric power is the rate at which electric energy is transferred
It is measured in watts (W)
Power is calculated using the formula: P = V*I, where P is power, V is voltage, and I is current

Electric charge is a fundamental property of matter, existing in two types: positive and negative
Like charges repel each other, while opposite charges attract each other
Charge is measured in coulombs (C), and its unit is defined as the quantity of electric charge that flows through a cross-sectional area of a conductor in one second, with a constant current of one ampere

Electric current is the flow of electric charge, measured in amperes (A)
Current is the rate of flow of charge, not the amount of charge itself, and is defined as one coulomb per second
Ohm's law relates current to voltage and resistance: I = V/R, where I is current, V is voltage, and R is resistance

Electric potential, or voltage, is the potential difference between two points, measured in volts (V)
Voltage is the "pressure" that drives electric current, and is defined as the energy required to move a unit of electric charge between two points
Electric potential energy is converted to kinetic energy as charge flows through a circuit

Resistance is the opposition to the flow of electric charge, measured in ohms (Ω)
Resistance depends on the material, length, and cross-sectional area of a conductor, and is defined as the ratio of voltage to current: R = V/I
Ohm's law relates resistance to voltage and current: R = V/I, where R is resistance, V is voltage, and I is current

Electric circuits consist of conductors, resistors, and sources of voltage
Series circuits have components connected one after the other, with the current being the same throughout
Parallel circuits have components connected between the same two points, with the voltage being the same throughout
Kirchhoff's laws govern electric circuits:
- Junction rule: the sum of currents entering a junction is equal to the sum of currents leaving a junction
- Loop rule: the sum of voltage changes around a closed loop is zero

Electric power is the rate at which electric energy is transferred, measured in watts (W)
Power is calculated using the formula: P = V*I, where P is power, V is voltage, and I is current
Electric power represents the rate of doing work, and is a measure of the energy transferred per unit time