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Energy and its Forms
Quick questions on Electrical energy use and cost: N(T) Science Energy and its Forms
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 appliances change electrical energy?Show answer
Every electrical appliance takes in electrical energy and changes it into a useful form, usually with some wasted as heat. For example, a lamp changes electrical energy into light, a kettle changes it into heat, a fan changes it into kinetic energy (movement), and a radio changes it into sound. Knowing the useful change for a common appliance is a frequent exam question.
What is power?Show answer
The power of an appliance tells you how fast it uses electrical energy. Power is measured in watts (W) or kilowatts (kW), where one kilowatt is 1000 watts.
What is the kilowatt-hour?Show answer
Electricity companies measure the energy you use in kilowatt-hours (kWh). One kilowatt-hour is the energy used by a 1 kW appliance running for 1 hour. It is sometimes just called a "unit" of electricity.
What is working out the cost?Show answer
Once you know the energy in kilowatt-hours, the cost is simple:
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