Conductance

Definition

Conductance is a measure of a material's ability to allow the flow of electric current. It is the reciprocal of resistance and is an important concept in understanding the behavior of resistors in electrical circuits.

5 Must Know Facts For Your Next Test

1. Conductance is the reciprocal of resistance, and is measured in Siemens (S), the unit of electrical conductance.
2. Conductance is an important factor in determining the behavior of resistors in series and parallel circuits, as it affects the overall resistance of the circuit.
3. In a series circuit, the total conductance is the sum of the individual conductances, while in a parallel circuit, the total conductance is the sum of the individual conductances.
4. Conductance is directly proportional to the cross-sectional area of a conductor and inversely proportional to the length of the conductor, as described by Ohm's law.
5. High-conductance materials, such as metals, have a low resistance to the flow of electric current, while low-conductance materials, such as insulators, have a high resistance to the flow of electric current.

Review Questions

• Explain how conductance is related to resistance in the context of Ohm's law.
  • According to Ohm's law, the current through a conductor is directly proportional to the voltage applied across it and inversely proportional to the resistance of the conductor. Conductance, being the reciprocal of resistance, is directly proportional to the current and voltage. Therefore, conductance can be used to describe the ease with which electric current flows through a material, with higher conductance indicating lower resistance and vice versa.
• Describe how conductance affects the behavior of resistors in series and parallel circuits.
  • In a series circuit, the total conductance is the sum of the individual conductances of the resistors. This means that the overall resistance of the circuit is reduced, as the current has multiple paths to flow through. Conversely, in a parallel circuit, the total conductance is the sum of the individual conductances, which increases the overall conductance of the circuit and reduces the overall resistance. This allows the current to be distributed more evenly among the parallel branches, making the circuit more efficient.
• Analyze how the physical properties of a conductor, such as cross-sectional area and length, influence its conductance.
  • According to Ohm's law, the conductance of a material is directly proportional to its cross-sectional area and inversely proportional to its length. This means that a conductor with a larger cross-sectional area will have a higher conductance, as it can accommodate more charge carriers and allow for a greater flow of electric current. Conversely, a longer conductor will have a lower conductance, as the increased length presents more resistance to the flow of current. These physical properties are important considerations when designing and analyzing electrical circuits, as they directly impact the overall conductance and resistance of the system.

Related terms

Resistance: Resistance is a measure of the opposition to the flow of electric current in a material or circuit.

Ohm's Law: Ohm's law states that the current through a conductor is directly proportional to the voltage applied across it, and inversely proportional to the resistance of the conductor.

Electrical Conductivity: Electrical conductivity is a measure of a material's ability to conduct electric current, and is the reciprocal of electrical resistivity.