Ampere

Definition

The ampere (symbol: A) is the base unit of electric current in the International System of Units (SI). It is the constant flow of one coulomb of electrical charge per second and is a fundamental measure of the strength of an electric current.

5 Must Know Facts For Your Next Test

1. The ampere is one of the seven base units of the SI system, along with the meter, kilogram, second, kelvin, mole, and candela.
2. Electric current, measured in amperes, is the flow of electric charge through a cross-section of a conductor, such as a wire.
3. Ohm's law, which states that the voltage across a resistor is proportional to the current flowing through it, is fundamental to understanding the role of the ampere in electrical circuits.
4. In parallel circuits, the total current is the sum of the currents in each branch, and the ampere is used to measure the current in each branch and the total current.
5. The ampere is also used to measure the strength of electromagnetic fields, as it is the fundamental unit of magnetic flux density.

Review Questions

• Explain how the ampere is defined and how it relates to the flow of electric charge.
  • The ampere is defined as the constant flow of one coulomb of electrical charge per second. This means that an electric current of one ampere is the flow of one coulomb of charge, which is approximately $6.24 \times 10^{18}$ electrons, past a given point in an electrical circuit in one second. The ampere is a fundamental measure of the strength of an electric current and is essential for understanding the behavior of electrical circuits and the flow of charge through them.
• Describe the role of the ampere in Ohm's law and its application in understanding electrical circuits.
  • Ohm's law, which states that the voltage (V) across a resistor is proportional to the current (I) flowing through it and the resistance (R), is expressed as V = IR. The ampere is a key component of Ohm's law, as it is the unit used to measure the electric current flowing through a circuit. Understanding the relationship between voltage, current, and resistance, as described by Ohm's law, is crucial for analyzing and designing electrical circuits, as the ampere is used to quantify the flow of charge and the strength of the current.
• Analyze the role of the ampere in the context of parallel circuits and its importance in understanding the distribution of current in such circuits.
  • In a parallel circuit, the total current is the sum of the currents in each branch, and the ampere is used to measure the current in each branch and the total current. The ampere is essential for understanding how current is distributed in a parallel circuit, as the current in each branch is inversely proportional to the resistance of that branch, according to Ohm's law. By using the ampere to measure the current in each branch and the total current, you can analyze the behavior of the circuit, determine the current in each component, and ensure that the circuit is operating within safe and efficient parameters.

Related terms

Electric Current: The rate of flow of electric charge, measured in amperes, through a given cross-section of an electrical conductor.

Coulomb: The SI unit of electric charge, equal to the amount of charge transported by a constant current of one ampere flowing for one second.

Ohm's Law: The relationship between voltage, current, and resistance in an electrical circuit, stated as V = IR, where V is voltage, I is current, and R is resistance.