Voltage

Definition

Voltage, also known as electrical potential difference, is the driving force that pushes electric charge through a circuit. It is the measure of the potential energy difference between two points in an electrical system, and it is the key factor that determines the flow of electric current.

5 Must Know Facts For Your Next Test

1. Voltage is the driving force that pushes electric charge through a circuit, and it is the key factor that determines the flow of electric current.
2. Voltage is measured in units of volts (V), which represent the potential energy difference between two points in an electrical system.
3. The potential difference between two points in an electric field is the work done per unit charge in moving a test charge between those points.
4. Electromotive force (EMF) is the voltage or potential difference generated by a source of electrical energy, such as a battery or generator, that drives the flow of electric current in a circuit.
5. Voltage is a fundamental concept in the study of electrochemical processes, as it is directly related to the spontaneity and extent of redox reactions that occur in electrochemical cells.

Review Questions

• Explain the relationship between voltage and the flow of electric current in a circuit.
  • Voltage is the driving force that pushes electric charge through a circuit, and it is the key factor that determines the flow of electric current. The higher the voltage, the greater the potential energy difference between two points in the circuit, and the more strongly the electric charges will be pushed to flow from the higher potential to the lower potential. This flow of electric charge is what we call electric current, and the rate of this flow is directly proportional to the voltage difference between the two points in the circuit.
• Describe how voltage is related to the work done in moving a test charge between two points in an electric field.
  • The potential difference, or voltage, between two points in an electric field is directly related to the work done per unit charge in moving a test charge between those two points. Specifically, the voltage between two points is equal to the work done per unit charge in moving a test charge from one point to the other. This relationship is expressed mathematically as $V = W/q$, where $V$ is the voltage, $W$ is the work done, and $q$ is the charge of the test particle. This connection between voltage and the work done in an electric field is a fundamental principle in the study of electrochemical processes, as it allows us to quantify the energy changes associated with the movement of charged species.
• Analyze the role of voltage in the spontaneity and extent of redox reactions in electrochemical cells.
  • Voltage is a critical factor in determining the spontaneity and extent of redox reactions that occur in electrochemical cells. The voltage, or potential difference, between the two electrodes in an electrochemical cell is directly related to the Gibbs free energy change ($\Delta G$) of the overall redox reaction. Specifically, the voltage is given by the equation $V = -\Delta G/nF$, where $n$ is the number of electrons transferred in the reaction and $F$ is the Faraday constant. This relationship means that the higher the voltage, the more favorable the redox reaction will be, and the greater the extent to which it will occur. Voltage is therefore a key parameter in understanding and predicting the behavior of electrochemical systems, such as batteries, fuel cells, and corrosion processes.

Related terms

Electric Potential: Electric potential is the potential energy per unit charge at a given point in an electric field. It represents the work done per unit charge in moving a test charge from infinity to that point.

Potential Difference: Potential difference, also called voltage, is the difference in electric potential between two points in an electric field. It is the work done per unit charge in moving a test charge between these two points.

Electromotive Force (EMF): Electromotive force (EMF) is the voltage or potential difference generated by a source of electrical energy, such as a battery or generator, that drives the flow of electric current in a circuit.