web viewgcse physics revision – p1 – quarter 1 ... a lot of energy is wasted as thermal...

GCSE Physics revision – P1 – Quarter 1 – Energy – v2

Q2. The diagrams show the cross-section of three double glazed windows.

The gap between the two sheets of glass can be filled with either air or a mixture of air and argon.

The U-values for different types of double glazed windows, using different types of glass X and Y, are given in the table.

Type of window 12 mm gap 16 mm gap 20 mm gap

1 Glass type X with air 2.9 2.7 2.8

2 Glass type X with air and argon 2.7 2.6 2.6

3 Glass type Y with air 1.9 1.8 1.8

4 Glass type Y with air and argon 1.6 1.5 1.5

(a) Which type of window, 1, 2, 3 or 4 is the least energy efficient?

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(b) Which two windows should be compared to decide if adding argon to the gap improves the energy efficiency of the window?

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(c) A householder is going to buy new windows. The sales assistant recommends that the householder buys windows with a 20 mm gap. These windows are much more expensive than those with a 16 mm gap.

It is not worth the householder paying the extra cost to buy 20 mm windows rather than 16 mm windows.

Explain this in terms of energy efficiency.

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(d) Windows are given an energy rating, from A down to G. The diagram shows the energy label from one type of double glazed window.

All new double glazed windows must have an energy rating of C or above.Windows having a C rating have a U-value of 1.9.

Which windows given in the table would the householder be unable to buy?

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(e) Glass transmits infrared radiation and visible light. The amount transmitted depends on the type and thickness of the glass. The data from tests on two different types of glass is displayed in the

graph below.

A homeowner has a glass conservatory built on the back of the house. The homeowner tells the builder that the inside of the conservatory should stay as cool as possible throughout the summer.


Explain why the builder uses ‘Type B’ glass for the conservatory.

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(Total 7 marks)

Q3. The picture shows a solar-powered aircraft. The aircraft has no pilot.

Photo by NASA.

(a) Use words from the box to complete the following sentence.

electrical heat light sound

Solar cells are designed to transform .............................................................. energy into

.............................................................. energy.(2)

(b) On a summer day, 175 000 joules of energy are supplied to the aircraft’s solar cells every second. The useful energy transferred by the solar cells is 35 000 joules every second.


(i) Use the equation in the box to calculate the efficiency of the solar cells.

Show clearly how you work out your answer.

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Efficiency = ..............................................................(2)

(ii) What happens to the energy that is not usefully transferred by the solar cells?

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(c) The aircraft propellers are driven by electric motors. As well as the solar cells, there are fuel cells that provide additional power to the electric motors.

(i) Suggest one advantage of the aircraft having fuel cells as well as the solar cells.

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(ii) Give one environmental advantage of using electric motors to drive the aircraft propellers rather than motors that burn a fuel.

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(iii) Eventually, the designers want to produce an unmanned aircraft that can fly at twice the height of a passenger jet for up to six months.

Suggest one possible use for an aircraft such as this.

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(Total 8 marks)

Q4. (a) The block diagram shows the important parts of a coal burning power station.

Use words from the box to complete the block diagram

boiler condenser furnace generator

(2)

(b) The diagram shows the energy transformations in a coal burning power station.

Calculate the efficiency of the power station.Write down the equation you use, and then show clearly how you work out your answer.

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Efficiency = ............................................(2)

(c) Draw a ring around the correct answer to complete the following sentence.


If fewer coal burning power stations are used to generate electricity the amount of

decrease.

not change.

increase.

carbon dioxide emitted into the atmosphere will

(1)

(d) Some types of power station generate electricity by burning a biofuel.

Give one example of a biofuel.

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(e) Nuclear power stations generate electricity without burning a fuel.

Name the process by which a nuclear fuel provides the energy needed to generate electricity.

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(Total 7 marks)

Q5. Power stations are usually not very efficient. A lot of energy is wasted as thermal energy. The diagrams show the percentage of energy transferred by two coal-burning power stations.

(a) Write the two missing figures in the boxes on the diagrams (next page).(2)

(b) Which power station is the most efficient overall, the normal power station or the combined heat and power station? Give reasons for your answer.

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(c) Some heat energy released from burning coal on an open fire is emitted by radiation. Tick ( ) the main type of electromagnetic radiation emitted by hot coal.

Type ofelectromagnetic radiation

Tick( )

gamma

infra red

ultraviolet

X-ray

1)

(d) Radiation can be reflected or absorbed when it strikes a surface. What type of surface is a poor reflector but a good absorber of radiation?

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(1)(Total 6 marks)

Q6. The bar charts show the rate of energy loss from the body of a runner at the start of a marathon race and half way through the race.

(a) It is important that the energy loss by evaporation increases during the race.

Explain why.

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(b) At the end of the marathon the runner covers herself in a silvered space blanket.

Explain how the space blanket helps keep the runner warm.

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(Total 4 marks)

Q7. (a) The diagram shows hot water being poured into a mug.

(i) Complete the sentence by choosing the correct words from the box. Each word may be used once or not at all.

air mug table water

Heat energy is being transferred from the ...................................................... to

the ........................................................... .(1)

(ii) When will this transfer of heat energy stop?

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(b) In the box are the names of four types of fuel used to heat homes.

coal gas oil wood

Which one of these types of fuel is renewable?

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(c) The diagram shows where heat energy is lost from a house.

(i) Complete the sentences by choosing the correct words from the box. Each word may be used once or not at all.

conduction conductor convection electric evaporation insulator

The amount of heat energy lost through the windows by

....................................................... can be reduced by using thick curtains. The

curtains trap a layer of air and air is a good ................................................... .

The curtains will also stop .................................................... currents pulling

cold air into the room through small gaps in the window.(3)

(ii) Write down one other way of reducing heat loss from a house.

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(Total 7 marks)

Q8. The diagram shows the label from a new freezer.

(a) An old freezer has an energy consumption per year of 350 kWh.

Use the equation in the box to calculate the extra cost of using the old freezer for one year compared with using a new ‘A’ rated freezer.

total cost = number of kilowatt-hours × cost per kilowatt-hour

Assume 1 kilowatt-hour (kWh) of energy costs 12 p.


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Extra cost per year = £ ..............................(2)

(b) The price of the new freezer was reduced in a sale.

Reducing the price reduces the payback time for replacing the old freezer from 12 years to 9 years.

Calculate, in pounds, how much the new freezer was reduced in the sale.


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Price reduced by = £ ........................................(2)

(c) An advertisement in a shop claims that:


‘Replacing an old freezer with a new ‘A’ rated freezer will benefit the environment.’

Do you agree that replacing the freezer will benefit the environment?

Answer yes or no. ..............................

Explain the reasons for your answer.

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(Total 6 marks

Q9. The drawing shows parts of a house where it is possible to reduce the amount of energy lost.

(a) Give one way in which the amount of energy lost can be reduced from each of the following parts of the house.

1, 2 and 4 ....................................................................................................................

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(b) Energy consumption can be reduced by using a more efficient boiler or more efficient light bulbs.

What is meant by a more efficient light bulb?

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(Total 4 marks)

Q10. The diagram shows a section through a gas oven.

Use words from the list to complete the sentences.

conduction convection insulation radiation resistance

The outside of the door gets hot because energy is transferred through

the door by ...........................................................................................................................

Energy is transferred from the gas flame to the rest of the oven by the movement of air.

This type of energy transfer is called ..................................................................................

The walls of the oven are packed with fibreglass to reduce energy transfer. Energy transfer

is reduced because fibreglass provides good .......................................................................

The outside of the cooker is white and shiny.

This reduces energy transfer by ...........................................................................................(Total 4 marks)

Q11. The diagram shows a fridge-freezer.


(a) By which method is heat transferred through the walls of the fridge-freezer?

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(b) The inside of the fridge is at 4 °C. The inside of the freezer is at –18 °C.

Into which part of the fridge-freezer will the rate of heat transfer be greater?

Draw a ring around your answer.

the fridge the freezer

Give a reason for your answer.

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(c) The outside surface of the fridge-freezer is white and shiny.

Give two reasons why this type of surface is suitable for a fridge-freezer.

1 ..................................................................................................................................

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(Total 4 marks)

Q12. The drawing shows water being heated in a metal saucepan.


a) Explain, in terms of the particles in the metal, how heat energy is transferred through the base of the saucepan.

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(b) Energy is transferred through the water by convection currents. Explain what happens to cause a convection current in the water. The answer has been started for you.

As heat energy is transferred through the saucepan, the water particles at the bottom

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(c) Some energy is transferred from the hotplate to the air by thermal radiation. What is meant by thermal radiation?

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(Total 6 marks)


Q13. There is an increasing demand for electricity and the reserve of fossil fuels is decreasing. A way to meet increasing demand for electricity is to build new nuclear power stations. Some people feel that no new nuclear power stations should be built because of the risks associated with nuclear fuels.

(a) Outline the arguments that a scientist working in the nuclear power industry could use to justify the building of more nuclear power stations in the future.

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(b) Nuclear waste is a problem that must be dealt with. One possible solution would be to bury the waste deep underground.

Suggest one reason why some people are against burying nuclear waste.

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(c) Electricity can also be generated using renewable energy sources.

Look at this information from a newspaper report.

• The energy from burning bio-fuels, such as woodchip and straw, can be used to generate electricity.

• Plants for bio-fuels use up carbon dioxide as they grow.

• Farmers get grants to grow plants for bio-fuels.

• Electricity generated from bio-fuels can be sold at a higher price than electricity generated from burning fossil fuels.

• Growing plants for bio-fuels offers new opportunities for rural communities.

Suggest why, apart from the declining reserves of fossil fuels, power companies should use more bio-fuels and less fossil fuels to generate electricity.

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(Total 7 marks)

web viewgcse physics revision – p1 – quarter 1 ... a lot of energy is wasted as thermal...

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