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volt

Primary Information
Secondary Information

Definition

The volt (V) is the SI unit of electric potential difference. It is named after Alessandro Volta, an Italian physicist who invented the voltaic pile, the first battery.

One volt is defined as the difference in electric potential between two points in a circuit when one coulomb of charge moves between them and does one joule of work.

Volts can be measured using a voltmeter. A voltmeter is a device that measures the difference in electrical potential between two points.

Volts are used in many different ways, including in batteries, power supplies, and electrical circuits. They are also used to measure the voltage of lightning strikes.

How can the word be used?

The power supply provides 120 volts.

volt

Different forms of the word

Noun: the unit of electromotive force, potential difference, or electrical potential.

Adjective: of or relating to a volt.

Etymology

The word "volt" is named after the Italian physicist Alessandro Volta (1745-1827), who invented the voltaic pile, the first battery.

The first recorded use of the word "volt" was in 1881.

Question

What is a volt?

AQA Science Exam Question and Answer

Question:

Define the concept of voltage (volt) in electricity. Explain how voltage difference between two points in a circuit influences the flow of electric current.

Answer:

Voltage, often measured in volts (V), is a fundamental concept in electricity that represents the electric potential difference between two points in an electrical circuit. It indicates the amount of energy carried by electric charges as they move between those points.

The voltage difference between two points influences the flow of electric current through a conductor. When there is a higher voltage at one point compared to another, it creates an electric potential gradient, prompting charged particles (usually electrons) to move from the higher potential point to the lower potential point. This movement of charged particles constitutes an electric current.

According to Ohm's law, the current (I) flowing through a conductor is directly proportional to the voltage (V) and inversely proportional to the resistance (R) of the circuit, expressed by the equation I = V/R. Therefore, a higher voltage difference leads to a greater electric current flow, provided the resistance remains constant.

In practical terms, varying voltage levels are essential for powering various devices and appliances. For example, household outlets provide a standard voltage (e.g., 120V or 230V), which powers devices when they are connected to the circuit. Understanding voltage and its relationship with current and resistance is vital for safely and effectively using electrical systems in our everyday lives.