Ohmic conductor

• What is an ohmic conductor?

  An ohmic conductor is a conductor that has a constant resistance at a constant temperature.
• How does the resistance of a conductor change with temperature?

  Generally, when the temperature of a conductor increases, its resistance increases.
• What is a fixed resistor?

  A fixed resistor is designed to have a constant resistance value.
• How can fixed resistors be used in circuits?

  They can be used to plan how currents and potential differences are distributed around a circuit.
• What type of conductor are wires considered to be?

  Wires are also a type of ohmic conductor.
• What happens to the ohmic properties of conductors at extreme temperatures?

  Both fixed resistors and wires can lose their ohmic properties at extreme temperatures.
• What does the IV graph for an ohmic conductor look like?

  The IV graph for an ohmic conductor is a straight line through the origin.
• What do the axes of an IV graph represent?

  The horizontal axis represents potential difference, and the vertical axis represents current.
• What does it mean when the IV graph passes through the origin?

  It means that there cannot be a current through the conductor without a potential difference and vice versa.
• What is the relationship between current and potential difference for ohmic conductors?

  The potential difference is always proportional to the current.
• How can we mathematically express the relationship between potential difference and current?

  We can express it as $V =$$kI$, where $k$ is a constant value.
• What does rearranging $V =$$kI$ to $V/I =$$k$ tell us?


  It tells us that the constant value $k$ is the resistance of the component.
• Why is resistance considered a constant value for ohmic conductors?

  Resistance is constant because we are looking at an ohmic conductor with a straight line IV graph.
• How does the gradient of the IV graph relate to resistance?

  The steeper the gradient of the graph, the smaller the resistance of the resistor.
• How is the gradient of the IV graph calculated?

  The gradient is calculated by dividing the change in current by the change in potential difference.
• What does a steeper graph indicate for a 10 Ohm resistor compared to a 5 Ohm resistor?

  A steeper graph indicates a smaller resistance, such as 5 Ohms, compared to a shallower graph for a larger resistance, such as 20 Ohms.
• What are the key features of the IV graph for ohmic conductors?

  • Straight line through the origin
  • Horizontal axis: potential difference
  • Vertical axis: current
  • Linear relationship between current and potential difference
• What is the significance of the constant $k$ in the equation $V =$$kI$?


  • $k$ represents the resistance of the component
  • Resistance is constant for ohmic conductors
• How does resistance affect the gradient of the IV graph?

  • Steeper gradient = smaller resistance
  • Shallower gradient = larger resistance
• What happens to the IV graph if the potential difference is reversed?

  • The current must also be reversed
  • Both values remain positive or negative
• What is the relationship between current and potential difference when the potential difference doubles?

  • The current must also double
  • This is due to the proportional relationship
• What are the implications of the IV graph passing through the origin?

  • No current without potential difference
  • No potential difference without current