4.3.4 Internal Resistance

• Match the term with its definition:

  Internal Resistance ↔️ Resistance within the power source

  External Resistance ↔️ Resistance in the external circuit
• The electrolyte inside a power source has resistance that impedes current flow.
• Conductors with higher resistivity have higher internal resistance.
• What is internal resistance in a power source?

  Resistance within the source
• Smaller power sources have higher internal resistance


  True
• Internal resistance is affected by the material, size, and temperature of the power source

  True
• Higher temperatures can increase the internal resistance of a power source


  True
• Internal resistance causes the terminal voltage to be lower than the source's open-circuit voltage


  True
• Internal resistance causes a voltage drop within the power source.


  True
• Internal resistance decreases terminal voltage as current increases.


  True
• The terminal voltage equation is: Open-Circuit Voltage - (Internal Resistance × Current)
• What type of conductors increase internal resistance?

  Higher resistivity
• Which component in a power source contributes to internal resistance due to its inherent resistance?

  Electrodes
• External resistance has no effect on the terminal voltage of the power source.

  True
• Internal resistance limits the maximum power transfer in a circuit.


  True
• Why does internal resistance limit the maximum power that can be transferred to the external circuit?

  Power is lost
• The equation for terminal voltage shows that as current increases, the terminal voltage decreases.
• What is the unit of internal resistance in the terminal voltage equation?

  Ohms
• Internal resistance causes energy to be lost as heat within the power source.


  True
• Internal resistance is distinct from external resistance.
• What is one component that contributes to internal resistance?

  Resistance of the electrodes
• Which factor increases internal resistance in a power source?

  Smaller size
• Order the effects of internal resistance on circuit behavior:

  1️⃣ Terminal Voltage Drop

  2️⃣ Power Transfer Limitation

  3️⃣ Efficiency Reduction
• Internal resistance limits the maximum power that can be transferred to the external circuit.
• Internal resistance limits the maximum power that can be transferred to the external circuit
• Internal resistance reduces the efficiency of power transfer
• The terminal voltage is always lower than the open-circuit voltage due to internal resistance.


  True
• Higher temperatures can increase internal resistance.


  True
• The resistance of the electrolyte within a power source contributes to internal resistance.


  True
• What does higher internal resistance in a power source lead to in terms of efficiency?

  Lower overall efficiency
• What effect does internal resistance have on the efficiency of power transfer?

  Reduces efficiency
• Higher internal resistance leads to lower efficiency of power transfer.

  True
• The open-circuit voltage is always higher than the terminal voltage in a circuit with internal resistance.


  True
• If the open-circuit voltage is 12V, the internal resistance is 2Ω, and the current is 3A, the terminal voltage is 6V.
• The efficiency of power transfer is reduced by higher internal resistance.
• Match the effect with its cause:

  Terminal Voltage Drop ↔️ Current through internal resistance

  Reduced Efficiency ↔️ Power dissipated in internal resistance
• What is internal resistance in a power source?

  Resistance within the source
• What effect does higher internal resistance have on efficiency?

  Reduces overall efficiency
• Why is internal resistance considered when designing electrical circuits?

  Ensure optimal performance
• Internal resistance opposes the flow of current