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Basic Circuit Concepts
Quick questions on Electrical power and energy explained: O-Level Electronics Basic Circuit Concepts
4short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is power is the rate of energy transfer?Show answer
Electrical power is the rate at which a component converts electrical energy into other forms such as heat, light or motion. The basic equation is:
What is the three forms of the power equation?Show answer
Because Ohm's law gives , you can substitute to get two more useful forms:
What is energy is power times time?Show answer
Electrical energy transferred is the power multiplied by the time for which it flows:
What is the kilowatt-hour?Show answer
The joule is a small unit, so household energy is measured in kilowatt-hours (). One kilowatt-hour is the energy used by a device running for one hour. To find the cost of running a device:
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