4.2.1 Potential Difference and Electromotive Force (EMF)

• EMF is the maximum potential difference a source can provide when no current
• The potential difference across a circuit component allows energy transfer.


  True
• Match the quantity with its definition:

  Potential Difference (V) ↔️ Work done per unit charge in moving a charge between two points

  Electromotive Force (EMF) ↔️ Maximum potential difference a source can provide when no current is flowing
• Potential difference drives current flow through a circuit
• Potential difference drives current through a circuit
• Potential difference measures energy transferred per unit charge
• What happens to the potential difference across a circuit component?

  Causes electric current to flow
• What is potential difference measured across to determine its resistance?

  Resistor
• Kirchhoff's Voltage Law states that the sum of all potential differences around a closed loop equals zero.


  True
• What does Kirchhoff's Voltage Law state about the sum of voltages in a closed loop?

  ∑V = 0 around a closed loop
• In a circuit with a 12V battery and two resistors of 4Ω and 2Ω in series, what is the current flowing through the circuit as calculated using KVL?

  2A
• What is the definition of potential difference (V) in electrical terms?

  Work done per unit charge
• Kirchhoff's Voltage Law states that the sum of all potential differences around a closed loop must equal zero
• What is the unit of potential difference?

  Volt
• Kirchhoff's Voltage Law is expressed mathematically as ∑V = 0
• Match the quantity with its definition:

  Potential Difference ↔️ Work done per unit charge

  Electromotive Force (EMF) ↔️ Maximum potential difference with no current
• Steps to apply Kirchhoff's Voltage Law (KVL) in a circuit with a 12V battery and two resistors in series

  1️⃣ Apply KVL around the loop

  2️⃣ Use Ohm's Law to express voltage drops

  3️⃣ Substitute voltage drops into KVL equation
• Kirchhoff's Voltage Law states that the sum of all potential differences around any closed loop in a circuit must equal zero
• The voltage drop across resistor R1 in a circuit can be expressed as $I \cdot 4Ω$
• What is the current in a circuit with a 12V battery and two resistors of 4Ω and 2Ω in series?

  $I =$$2A$
• The voltage drop across a resistor in a circuit can be expressed using Ohm's Law
• The voltage drop across a 2Ω resistor in the same circuit is $4V$
• Potential difference is a measure of energy transferred per unit charge.


  True
• The EMF of a source represents the maximum potential difference it can maintain across its terminals
• Why is potential difference measured in volts?

  Work done per unit charge
• EMF is the upper limit on the potential difference in a circuit.

  True
• What does potential difference represent in electrical terms?

  Work done per unit charge
• What is the definition of potential difference in an electric field?

  Work done per unit charge
• EMF is the maximum potential difference a source can maintain across its terminals when no current is flowing.


  True
• Match the aspect of potential difference and EMF with their correct definition:

  Potential Difference (V) ↔️ Work done per unit charge

  Electromotive Force (EMF) ↔️ Maximum potential difference when no current flows
• Match the source of EMF with its correct description:

  Batteries ↔️ Convert chemical energy into electrical energy

  Generators ↔️ Convert mechanical energy into electrical energy

  Solar Cells ↔️ Convert light energy into electrical energy

  Thermocouples ↔️ Generate voltage from temperature difference
• Ohm's Law is used to calculate voltage drops using the formula V = IR.
• Kirchhoff's Voltage Law states that the sum of all potential differences around any closed loop in a circuit must equal zero.


  True
• What does Kirchhoff's Current Law state about the sum of currents at a junction?

  ∑I = 0 at a junction
• What is the definition of electromotive force (EMF) in electrical terms?

  Maximum potential difference
• The key difference between potential difference and EMF is that EMF is the maximum potential a source can maintain when no current flows.

  True
• What does Kirchhoff's Voltage Law state about the sum of potential differences in a closed loop?

  It must equal zero
• Potential difference drives the flow of electric current through a circuit.


  True
• What is the key difference between potential difference and electromotive force?

  Current flow versus maximum potential
• EMF represents the maximum potential a source can maintain across its terminals.


  True