Quick questions on Electrical power and energy (QCE Physics Unit 1)

6short 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 iA1?

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Often an oscilloscope or data-logger trace with

V

and

I

measured, asking for instantaneous and average power.

What is eA Paper 1?

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Multiple choice on which power formula is appropriate, and conversions between watts and kilowatt-hours.

What is eA Paper 2?

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Combined with the series-and-parallel dot point to find the power dissipated in each individual resistor of a small circuit, then total energy delivered by the battery over a stated time.

What is q1?

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State the unit of electrical energy used by utilities and convert

1 \text{ kWh}

to joules. [2 marks]

What is q2?

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2.0 \text{ kW}

kettle is plugged into a

240 \text{ V}

supply for

4.0

minutes. Calculate the current, the resistance, and the energy delivered. [4 marks]

What is q3?

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A Bundaberg shed runs a

3.0 \text{ kW}

motor with

85

per cent electrical efficiency. (a) Calculate the input power and the heat dissipated. (b) Calculate the energy bill for

6.0 \text{ h per day, 30 days}

0.30

dollars per kWh.

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