P1 2.1 Energy transfers and efficiency powerpoint

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Transcript P1 2.1 Energy transfers and efficiency powerpoint

P1.2.1 Energy transfers and efficiency

GCSE items that can be used to define successful outcomes for peer and self assessment activities

Assessment of practical work

Using Exam pro items to support successful outcomes

Learners will be able to test their progress against learning outcomes using questions taken from past AQA GCSE questions.

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Q1 Foundation

AQA-PH1FP-QP-Jun12 Q1 The appliances shown on the next slide transfer electrical energy to other types of energy.

The vacuum cleaner is designed to transfer electrical energy to kinetic energy.

a)Name the three other appliances which are also designed to transfer electrical energy to kinetic energy.

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Q1 cont. b) Which two of the following statements are true?

•A Appliances only transfer part of the energy usefully.

•B The energy transferred by appliances will be destroyed.

•C The energy transferred by appliances makes the surroundings warmer.

•D The energy output from an appliance is bigger than the energy input.

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Q1 mark scheme a) Washing machine, fan, drill 1 mark for each

3

b) A C 1 mark for each

2

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Q2 Foundation Exampro QM94R505

The diagram shows what happens to each 100 joules of energy from crude oil when it is used as petrol in a car.

The widths of the arrows show exactly how much energy is transferred in each particular way.

(a) Complete the diagram by adding the correct energy value alongside each arrow. (3)

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(b) Calculate how efficient the car engine is at transferring the energy

from petrol

into useful movement.

[Show your working].

(2)

(c) Two students are discussing the diagram.

The first says that

none

of the energy released from the crude oil is really lost.

The other says that

all

of the energy released from the crude oil is really lost.

What do you think?

Explain your answer as fully as you can.

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Q2 mark scheme

(a) A = B = 20, C = 60

3

(b)

evidence of or

20%/0.2 gains 1 mark

but

25%/0.25

or

figure consistent with B in part (a)

gains 2 marks 2

(c)

ideas that

“lost” energy is (also) transferred (in ways we don’t want) total amount of energy (before and after any transfer) remains the same energy becomes (progressively) more spread out/less easy to transfer again this applies to

all

the energy/even to the energy usefully transferred

each for 1 mark Version 2.0 Copyright © AQA and its licensors. All rights reserved.

Q3 higher

AQA-PH1HP-QP-Jan12 Q 6 The table on the next slide gives data about two types of low energy bulb.

(a) Both types of bulb produce the same useful power output.

(a) (i) Calculate the useful power output of the CFL.

Use the correct equation from the Physics Equations Sheet.

Show clearly how you work out your answer.

Useful power output = ................................................. W

(2 marks)

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Q3 contd.

(a) (ii)

Calculate the efficiency of the LED bulb.

Use the correct equation from the Physics Equations Sheet.

Show clearly how you work out your answer.

Efficiency = ......................................................

(1 mark)

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Q3 contd.

6 (b) Sketch and label a Sankey diagram for the CFL

(2 marks)

6 (c) LED bulbs are expensive. This is because of the large number of individual electronic LED chips needed to produce sufficient light from each bulb.

6 (c) (i) Use the data in the table to evaluate the cost effectiveness of an LED bulb compared to a CFL.

(2 marks)

6 (c) (ii) Scientists are developing brighter and more efficient LED chips than those currently used in LED bulbs.

Suggest one benefit of developing brighter and more efficient LED chips.

(1 mark)

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Q3 markscheme Version 2.0 Copyright © AQA and its licensors. All rights reserved.

Q3 markscheme contd. Version 2.0 Copyright © AQA and its licensors. All rights reserved.

Q3 markscheme contd. Version 2.0 Copyright © AQA and its licensors. All rights reserved.