Electronvolt

Electronvolt

The electronvolt (symbol: eV) is a unit of energy commonly used in the field of physics, particularly in particle physics, atomic physics, and condensed matter physics. It is defined as the amount of kinetic energy gained or lost by an electron when it is accelerated through an electric potential difference of one volt.

Definition

An electronvolt is equivalent to approximately 1.602176634 × 10^−19 joules (J). This value is derived from the elementary charge (e), which is the charge of a single electron, and the definition of the volt.

Usage

The electronvolt is a convenient unit of energy for many applications in physics because it is well-suited to the scale of energies involved in atomic and subatomic processes. For example, the energy levels of electrons in an atom are typically on the order of electronvolts.

In particle physics, energies are often expressed in multiples of electronvolts, such as kiloelectronvolts (keV), megaelectronvolts (MeV), gigaelectronvolts (GeV), and teraelectronvolts (TeV). For instance, the Large Hadron Collider (LHC) at CERN can accelerate particles to energies of several TeV.

Conversion to Other Units

The electronvolt can be converted to other units of energy. Some common conversions include:

• 1 eV = 1.602176634 × 10^−19 J
• 1 keV = 1,000 eV
• 1 MeV = 1,000,000 eV
• 1 GeV = 1,000,000,000 eV
• 1 TeV = 1,000,000,000,000 eV

Applications

Electronvolts are used in various fields of physics:

• In atomic physics, to describe the energy levels of electrons in atoms.
• In solid-state physics, to describe the energy bands in crystals.
• In nuclear physics, to describe the binding energy of nuclei.
• In particle physics, to describe the energies of particles in accelerators.

Related Concepts

• Binding energy
• Ionization energy
• Photon energy
• Work function

See Also

• Joule
• Volt
• Elementary charge
• Large Hadron Collider
• Particle accelerator