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Why does your electricity bill use kilowatt-hours?

A kilowatt describes a rate of energy transfer, while a kilowatt-hour describes an amount. A fictional constant 1.5-kilowatt load running for two hours uses three kilowatt-hours; real devices may vary their power during use.

2–3 min

Questions you could explore

  • What extra information turns a power rating into an energy estimate?

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How can a heat pump deliver more heat than its electricity input?

Energy4–5 minA heating device seems to promise something impossible when its heat output exceeds the electricity it uses. A heat pump's energy account includes another input: heat moved from its surroundings.

Energy

How does a photovoltaic cell turn light into electricity?

A solar cell can generate electricity without a turbine or other moving machinery. Light interacting with a semiconductor starts the process, but separating and collecting the resulting charges is what makes electrical output possible.

4–5 min

How does a photovoltaic cell turn light into electricity?

Energy4–5 minA solar cell can generate electricity without a turbine or other moving machinery. Light interacting with a semiconductor starts the process, but separating and collecting the resulting charges is what makes electrical output possible.

How does a wind turbine turn moving air into electricity?

Energy3–5 minA turbine's blades are only the visible beginning of the journey from wind to electricity. Their rotation drives a generator, though the machinery connecting those parts differs between turbine designs.

Why does your electricity bill use kilowatt-hours? | Speech Topic | speaking.app