Summarizing Electric Power and Energy

Summary

• Electric power \(P\) is the rate (in watts) that energy is supplied by a source or dissipated by a device.
• Three expressions for electrical power are

  \(P=\text{IV,}\)

  \(P=\cfrac{{V}^{2}}{R}\text{,}\)

  and

  \(P={I}^{2}R\text{.}\)

• The energy used by a device with a power \(P\) over a time \(t\) is \(E=\text{Pt}\).

Glossary

electric power

the rate at which electrical energy is supplied by a source or dissipated by a device; it is the product of current times voltage