Electronvolt (eV)
The electronvolt, symbolized as eV, is primarily used in atomic, nuclear, and particle physics. It is the energy gained by an electron moving through a one-volt potential. The electronvolt enables scientists to measure very small energy changes at the atomic scale. Introduced in the early 20th century, it is standard for describing energy in atoms, photons, and particles. The electronvolt adds the necessary precision in modern physics and works in conjunction with larger units, such as joules and kilojoules.
Kilowatt Hour (kWh)
The kilowatt-hour, symbolized as kWh, is a common unit in electricity billing and energy reporting. It is the energy used by a 1-kilowatt device for 1 hour, or 3.6 million joules. With the advent of electrification in the late 1800s and early 1900s, the kilowatt-hour made measuring electrical energy simpler for both utilities and customers. Its use is crucial for billing, energy management, and understanding electricity use in homes, industry, and renewable energy.