Voltage

Definition

Voltage, also known as electric potential difference, is the measure of electric potential energy per unit charge between two points in an electric field. It represents the work done to move a charge from one point to another and is a key factor in understanding how electrical energy is transferred within circuits and systems. Voltage influences the flow of current, determines the behavior of capacitors, and plays a crucial role in electromotive forces generated by sources like batteries.

5 Must Know Facts For Your Next Test

1. Voltage is measured in volts (V), where 1 volt equals 1 joule of energy per coulomb of charge.
2. The difference in voltage between two points creates an electric field that drives current flow through conductors.
3. In capacitors, the amount of stored charge is directly proportional to the voltage applied across them, following the relationship Q = CV.
4. Electromotive force (emf) refers to the voltage generated by a battery or other energy source, which can also be affected by internal resistance.
5. Voltage can be understood as a measure of the 'push' that drives electrical charges to move through a circuit.

Review Questions

• How does voltage influence the flow of current in a circuit?
  • Voltage acts as the driving force for current flow in a circuit. A higher voltage creates a stronger electric field, which encourages more charge carriers to move through the circuit. This relationship is described by Ohm's Law, where current is directly proportional to voltage and inversely proportional to resistance. Therefore, if the voltage increases while resistance remains constant, the current will also increase.
• Discuss how voltage is related to electric potential energy and the behavior of capacitors.
  • Voltage is fundamentally linked to electric potential energy as it represents the work done per unit charge to move charges within an electric field. In capacitors, voltage determines how much charge can be stored; higher voltages lead to more stored energy. The relationship can be expressed with the formula U = 1/2 CV², where U is the stored energy, C is capacitance, and V is voltage. This highlights how changes in voltage affect both the stored energy and overall function of capacitors.
• Evaluate the role of electromotive force and internal resistance in understanding voltage within electrical circuits.
  • Electromotive force (emf) represents the maximum voltage generated by a source like a battery under open-circuit conditions. However, real-world batteries have internal resistance that reduces the actual voltage available across terminals when under load. This interaction affects how effectively a battery can deliver current to a circuit. Understanding this helps analyze circuit performance and efficiency, as internal resistance leads to energy losses in the form of heat when current flows.

Related terms

Electric Potential Energy: The energy stored in an electric field due to the position of charged particles.

Current:

The flow of electric charge through a conductor, typically measured in amperes.

Capacitance:

The ability of a system to store electric charge, defined as the amount of charge stored per unit voltage.