Electricity: Electric Charge and Current

Electricity

Electric Charge

• Electric charge is a fundamental property of matter
• There are two types of electric charge: positive and negative
• Like charges repel each other, while opposite charges attract each other
• Charge is measured in coulombs (C)

Electric Current

• Electric current is the flow of electric charge
• It is measured in amperes (A)
• Current is the rate of flow of charge, not the amount of charge itself
• Ohm's law: I = V/R, where I is current, V is voltage, and R is resistance

Electric Potential (Voltage)

• 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

• 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

• 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

• 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

Electricity

Electric Charge

• 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

• 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 (Voltage)

• 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

• 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

• 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

• 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