watt second
Học thuậtThân thiện
Definition
Noun: A watt second is a derived unit of energy or work in the International System of Units (SI). It is defined as the amount of energy expended or work done when a power of one watt is sustained for a duration of one second.
Usage
This unit is used in physics and engineering to quantify small amounts of electrical energy, work, or heat. It is a practical unit for calculations involving electrical circuits, energy consumption in small devices, and in scientific contexts where energy is expressed in basic SI terms.
Examples
- The capacitor stored an energy of five watt seconds.
- To calculate the total energy, multiply the power in watts by the time in seconds to get the result in watt seconds.
- A single LED might consume a few thousand watt seconds of energy per hour of operation.
Advanced Usage
- Scientific Context: The watt second is dimensionally equivalent to the joule (J), which is the standard SI unit of energy. Therefore, 1 watt second = 1 joule. This equivalence is fundamental in physics, linking electrical power concepts to mechanical energy.
- Practical Application: While the joule is more common in general scientific writing, the term "watt second" can be explicitly used to emphasize the direct relationship between electrical power (watt) and time (second) in a specific calculation or measurement.
Variants and Related Words
- Joule (J): The SI unit of energy, work, and heat. It is synonymous with the watt second (1 J = 1 W·s).
- Watt (W): The SI unit of power, defined as one joule per second. It is the rate of energy transfer or conversion.
- Kilowatt-hour (kWh): A much larger unit of energy commonly used for electricity billing. 1 kWh = 3,600,000 watt seconds (or joules).
Synonyms
- Joule (J) (primary synonym)
Notes on Meaning
The term has one primary, precise scientific meaning. It is a compound unit formed from the base units of power (watt) and time (second). Its meaning is not figurative or idiomatic.
Noun
- a unit of electrical energy equal to the work done when a current of one ampere passes through a resistance of one ohm for one second