Thermal Energy Transfers

Physics 1 Conduction ●The transfer of energy by conduction involves particles, and how this transfer takes place. Candidates should understand in simple terms how the arrangement and movement of particles determine whether a material is a conductor or an insulator. Candidates should understand the role of free electrons in conduction through a metal. ●The use of kinetic theory to explain the different states of matter. Candidates should be able to recognise simple diagrams to model the difference between solids, liquids and gases. ●The particles of solids, liquids and gases have different amounts of energy. An understanding of specific latent heat is not required. ●The bigger the temperature difference between an object and its surroundings, the faster the rate at which energy is transferred by heating.

Physics 2 Convection ●The transfer of energy by convection, evaporation and condensation involves particles, and how this transfer takes place. Candidates should be able to use the idea of particles moving apart to make a fluid less dense, to explain simple applications of convection. ●The factors that affect the rate of evaporation and condensation. Candidates should be able to explain evaporation and the cooling effect this causes using the kinetic theory.

Physics 3 Radiation ●All objects emit and absorb infrared radiation. ●The hotter an object is the more infrared radiation it radiates in a given time. ●Dark, matt surfaces are good absorbers and good emitters of infrared radiation. ●Light, shiny surfaces are poor absorbers and poor emitters of infrared radiation. ●Light, shiny surfaces are good reflectors of infrared radiation. ●Solar panels may contain water that is heated by radiation from the Sun. This water may then be used to heat buildings or provide domestic hot water.

Physics 4 Specific Heat Capacity ●The specific heat capacity of a substance is the amount of energy required to change the temperature of one kilogram of the substance by one degree Celsius. E = m x c x θ

E is energy transferred in joules, J m is mass in kilograms, kg θ is temperature change in degrees Celsius, °C c is specific heat capacity in J / kg °C

●Evaluate different materials according to their specific heat capacities. Examples include the use of water, which has a very high specific heat capacity, oil-filled radiators and electric storage heaters containing concrete or bricks.

Physics 5 Energy Transfer and Insulation ●Compare ways in which energy is transferred in and out of objects by heating and ways in which the rates of these transfers can be varied. Examples should include the design of a vacuum flask, how to reduce the energy transfer from a building and how humans and animals cope with low temperatures. ●Evaluate the design of everyday appliances that transfer energy by heating, including economic considerations Examples include radiators and heat sinks. ●Evaluate the effectiveness of different types of material used for insulation, including U-values and economic factors including payback time. Examples include loft insulation and cavity wall insulation. ● Candidates should be able to explain the design of devices in terms of energy transfer, for example, cooling fins. ●The rate at which an object transfers energy by heating depends on:

■ surface area and volume ■ the material from which the object is made ■ the nature of the surface with which the object is in contact.

Candidates should be able to explain animal adaptations in terms of energy transfer, for example, relative ear size of animals in cold and warm climates. ●U-values measure how effective a material is as an insulator. Knowledge of the U-values of specific materials is not required, nor is the equation that defines a U-value. ●The lower the U-value, the better the material is as an insulator.

Physics 1 Conduction According to kinetic theory, all matter is made up of small particles. The particles are constantly moving. The diagram shows the arrangement of the particles in a solid; each circle represents one particle. Complete the diagram below to show the arrangement of the particles in a liquid and a gas.

Now describe the structure of solids, liquids and gases using kinetic theory.

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Explain, in terms of the particles, why gases are easy to compress.

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One kilogram of a gas has a much larger volume than one kilogram of a solid. Use kinetic theory to explain why.

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________________________________________________________________________________________________________ A substance can change from one state to another by heating or cooling it. Complete the diagram by naming the changes of state.

Describe the following in terms of energy, the movement of particles and the bonds between them.

A) Describe how a solid changes into a liquid when it is heated.

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B) Describe how a liquid changes into a gas when it is heated.

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C) Describe how a gas changes into a liquid when it is cooled.

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D) Describe how a liquid changes into a solid when it is cooled.

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________________________________________________________________________________________________________ Which of the following statements describes what happens to the particles in a solid when they are heated?

The particles start to vibrate around a fixed position.

The particles begin to move position.

The particles vibrate more and move apart.

Heat always flows from an area of ______________________ temperature to an area of ______________________ temperature. The ______________________ the temperature difference between an object and its surroundings, the ______________________ the rate at which energy is transferred. Conduction is heat transfer by the passing on of vibrations from one particle to the neighbouring particles. State which states of matter conduction happens in and explain your answer.

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What is the definition of a ‘conductor’? Give some examples of conducting materials.

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What is the definition of an ‘insulator’? Give some examples of insulating materials.

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What is the structure of an insulator like? You can give some examples of insulating materials to help you.

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Metals are the best conductors because they contain lots of ________________________________________________________ Explain how this makes conduction happen faster.

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Physics 2 Convection The diagram shows a metal pan being used to heat water. Energy from the gas flame is transferred through the metal pan by conduction and warms the water.

A) The particles nearest the source of heat (gas flame) gain energy and vibrate more.

B) This means that they become ____________________________________________

C) The particles then ____________________________

D) Away from the source of heat they lose their energy and vibrate less.

E) This means that they become ____________________________________________

F) The particles then ____________________________

This is called a convection current. Add this to the diagram above. Conduction and convection both require particles to happen; explain the difference in these heat transfers.

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Explain why convection cannot happen in solids.

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________________________________________________________________________________________________________ The picture shows a puddle of water in a road, after a rain shower. During the day, the puddle of water dries up and disappears.

The rate of evaporation (or condensation) is affected by several factors: 1) The surface area 2) The temperature 3) If there is a draught 4) The humidity

Increasing the surface area of a liquid will ________________________________________ the rate of evaporation.

Decreasing the temperature of a liquid will ________________________________________ the rate of evaporation.

Creating a draught of air across the liquid’s surface will ________________________________________ the rate of evaporation.

Decreasing the humidity of the air will ________________________________________ the rate of evaporation. The diagram shows the particles in a liquid. The liquid is evaporating.

How can you tell from the diagram that the liquid is evaporating?

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The temperature of the liquid in the container decreases as the liquid evaporates. Use kinetic theory to explain why.

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Physics 3 Radiation Infrared radiation is a wave of the electromagnetic spectrum (see Physics 19 the EM Spectrum) like light. It doesn’t need particles to work and travels at the speed of light. All objects emit and absorb infrared radiation.

What does emit mean? _______________________________________________________________

What does absorb mean? _______________________________________________________________

The _____________________ the temperature of an object the _____________________ infrared radiation it emits per second.

Explain why heat from the Sun must reach the Earth by infrared radiation and not conduction or convection.

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Which surfaces are good reflectors of infrared radiation? ________________________________________________________

Which surfaces are poor reflectors of infrared radiation? ________________________________________________________

Which surfaces are good absorbers of infrared radiation? ________________________________________________________

Which surfaces are poor absorbers of infrared radiation? ________________________________________________________

Which surfaces are good emitters of infrared radiation? ________________________________________________________

Which surfaces are poor emitters of infrared radiation? ________________________________________________________

Heat always flows from an area of ______________________ temperature to an area of ______________________ temperature.

The diagram shows the equipment a student used to investigate how the colour of a surface affects how fast it emits heat.

An equal volume of boiling water was poured into each metal can. The student then recorded the temperature of the water in each can every minute for ten minutes.

In which can would you expect the water to be at a lower temperature after ten minutes?

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Explain the reason for your answer.

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What temperature would the water in both cans eventually reach? ___________________________________________________

Why couldn’t the water go below this temperature?

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The diagram shows the design of a solar cooker. The cooker heats water using infrared radiation from the Sun. What type of material should be used for the inside of the large curved dish? Explain your answer.

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Which would be the best colour to paint the outside of the metal cooking pot? Explain your answer.

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Physics 4 Specific Heat Capacity What is meant by term ‘specific heat capacity’ of a substance?

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𝐸 = 𝑚 × 𝑐 × 𝜃

Symbol Quantity Units Unit Symbol

E

m

c

θ

Rearrange the equation to make m, c and then θ the subject.

If two materials that had the same mass were given the same amount of energy which of the following statements would be true?

The material with the lower specific heat capacity would reach the higher temperature.

The materials would reach the same temperature.

The material with the higher specific heat capacity would reach the higher temperature.

Complete this table by calculating the missing values. Give your answers to 1 decimal place.

E m c θ

2 4200 80

100 2100 50

7200 900 4

7200 390 4

1600 0.3 35

9 000 000 15 17

450 000 5.8 130

198 000 8.9 850

Physics 5 Energy Transfer and Insulation The drawing shows parts of a house where it is possible to reduce the amount of energy lost. Give one way in which the amount of energy lost can be reduced from each of the following parts of the house.

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_________________________________________ The U-values of a material is a measure how effective it is as an insulator.

The lower the U-value a material has the _________________________________________ the material is an insulator.

The payback time of something is the time it would take save the same amount of money as it cost to buy it in the first place. The table gives information about some ways of reducing the energy consumption in a house; calculate their payback times

Method of reducing energy consumption

Installation cost (£)

Annual saving on energy bills (£)

Payback time (years)

Cavity wall insulation 250 115

Jacket for hot water tank 12 35

Upgrade central heating controls 310 80

Double glazing 5280 160

Draught proofing 45 20

Loft insulation 175 60

The diagram shows the structure of a vacuum flask. A vacuum flask is designed to reduce the rate of energy transfer by heating processes. Describe how the design of a vacuum flask keeps the liquid inside hot.

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The diagram shows a car radiator. The radiator is part of the engine cooling system.

Liquid coolant, heated by the car engine, enters the radiator. As the coolant passes through the radiator, the radiator transfers energy to the surroundings and the temperature of the coolant falls. Why is the radiator painted black?

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The number of cooling fins affects the rate of energy transfer from the radiator. Explain how.

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Dessert foxes have larger ears than arctic foxes. Based on this observation what is the connection with surface area and rate of energy transfer? Explain your answer.

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Efficiency and Power

Physics 6 Energy Transformations ●Examples of energy transfers that everyday electrical appliances are designed to bring about. ●Describe the energy transfers and the main energy wastages that occur with a range of appliances. Common electrical appliances found in the home will be examined. Examples will not be limited to electrical appliances; however, in this case all the information would be given in the question. ●Energy can be transferred usefully, stored, or dissipated, but cannot be created or destroyed. ●When energy is transferred, only part of it may be usefully transferred; the rest is ‘wasted’.

Physics 7 Power ●The amount of energy an appliance transfers depends on how long the appliance is switched on and its power. ●To calculate the amount of energy transferred from the mains using:

E = P x t E is energy transferred in kilowatt-hours, kWh P is power in kilowatts, kW tis time in hours, h

This equation may also be used when: E is energy transferred in joules, J P is power in watts, W tis time in seconds, s

Candidates will not be required to convert between kilowatt-hours and joules.

Physics 8 Efficiency ●Wasted energy is eventually transferred to the surroundings, which become warmer. The wasted energy becomes increasingly spread out and so becomes less useful. ●To calculate the efficiency of a device using:

𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 =𝑢𝑠𝑒𝑓𝑢𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 𝑜𝑢𝑡

𝑡𝑜𝑡𝑎𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 𝑖𝑛 (× 100%)

𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 =𝑢𝑠𝑒𝑓𝑢𝑙 𝑝𝑜𝑤𝑒𝑟 𝑜𝑢𝑡

𝑡𝑜𝑡𝑎𝑙 𝑝𝑜𝑤𝑒𝑟 𝑖𝑛 (× 100%)

Candidates may be required to calculate efficiency as a decimal or as a percentage. ●Interpret and draw a Sankey diagram. Candidates should be able to use a Sankey diagram to calculate the efficiency of an appliance. ●Compare the efficiency and cost effectiveness of methods used to reduce ‘energy consumption’. The term ‘payback time’ should be understood. ●Given relevant data, candidates should be able to make judgements about the cost effectiveness of different methods of reducing energy consumption over a set period of time. This is not restricted to a consideration of building insulation but may include:

■ Low energy light bulbs and LED lighting ■ Replacing old appliances with energy efficient ones ■ Ways in which ‘waste’ energy can be useful, eg heat exchangers.

Physics 9 Cost ●To calculate the cost of mains electricity given the cost kilowatt-hour. This includes both the cost of using individual appliances and the interpretation of electricity meter readings to calculate total cost over a period of time.

Physics 6 Energy Transformations Energy can exist in many different forms or types. For each type of energy listed below explain what the word means and give examples of where we commonly find it.

Chemical ___________________________________________________________________________________________

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Elastic ___________________________________________________________________________________________

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Electric ___________________________________________________________________________________________

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Gravitational ___________________________________________________________________________________________

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Kinetic ___________________________________________________________________________________________

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Light ___________________________________________________________________________________________

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Nuclear ___________________________________________________________________________________________

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Sound ___________________________________________________________________________________________

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Thermal ___________________________________________________________________________________________

___________________________________________________________________________________________ What does the word potential mean? __________________________________________________________________________

Which of the energy types above can the word potential be applied to?

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The conservation of energy states that energy cannot be ___________________________ or ___________________________

Energy can stored, given out or transformed from ________________________________________________________________

This means that the energy we put into a device is ___________________________ the energy that we get out of a device. What is meant by the term ‘useful energy out’?

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What is meant by the term ‘wasted energy out’?

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Which of the lists has the most common wasted energy types?

Sound, kinetic and chemical

Thermal, kinetic and light

Sound, thermal and kinetic

Thermal, sound and light

Complete this table by identifying the energy transformations that are taking place in each device.

Device: Television Energy type in:

Useful energy type(s) out: Wasted energy type(s) out:

Device: Toaster Energy type in:

Useful energy type(s) out: Wasted energy type(s) out:

Device: Iron Energy type in:

Useful energy type(s) out: Wasted energy type(s) out:

Device: Desk lamp Energy type in:

Useful energy type(s) out: Wasted energy type(s) out:

Device: Hair dryer Energy type in:

Useful energy type(s) out: Wasted energy type(s) out:

Device: Fan heater Energy type in:

Useful energy type(s) out: Wasted energy type(s) out:

Device: Kettle Energy type in:

Useful energy type(s) out: Wasted energy type(s) out:

Device: Cordless drill Energy type in:

Useful energy type(s) out: Wasted energy type(s) out:

Device: Washing machine Energy type in:

Useful energy type(s) out: Wasted energy type(s) out:

Physics 7 Power What is meant by the power of an appliance?

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If I have two identical torches with identical new batteries, one has a bulb that is more powerful than the other; how could you tell

which is the most powerful bulb?

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Two cranes are used for 15 seconds to lift steel girders at a construction site. How could you tell which would be most powerful?

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If three students have a competition to push the same trolley down the S block corridor how could you tell which student is the least

powerful of the three?

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If two people buy the same type of ready meal and use their own microwaves to cook them how could you tell which person has

the most powerful microwave oven?

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𝐸 = 𝑃 × 𝑡

Symbol Quantity Units Unit Symbol

E Joules

P

t

Rearrange the equation to make P and then t the subject Complete this table by calculating the missing values. Give your answers to 1 or 2 decimal places.

E P t

60 300

2 500 254

600 75

175 000 21 600

9900 750

9072 54

Calculate the energy transferred when using a 60 W light bulb for 2 days.

When dealing with electrical energy the units that we have used so far are too small. Complete this table with the other units that we will use.

Symbol Quantity Units Unit Symbol

E

P

t hours

Electrical appliances left on standby use energy. The bar chart shows the power for the appliances that one family leaves on standby during a typical day.

Use the information in the graph and table already in the table to complete it.

Appliance Average ‘standby power’ ( )

Time kept of standby (Hours)

Energy transferred whilst on standby ( )

Compact stereo 14

DVD player 21

Microwave oven 23.5

Computer 20

TV 16

Video recorder 23

Which appliance wastes the most energy being on standby during a typical day? _______________________________________

Physics 8 Efficiency

Energy is never created or destroyed it is only ___________________________________________ from one type to another.

All wasted energy eventually gets transferred to the __________________________________ and becomes spread out.

This makes it difficult to ___________________________________________________________________

What does the term efficiency mean?

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What does it mean if a device or appliance is very efficient?

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What does it mean if a device or appliance is very inefficient (not efficient)?

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What affect does waste energy have on the surroundings?

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________________________________________________________________________________________________________ We can calculate the efficiency of a device using the energy or the power of the device in the following equations

𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 =𝑢𝑠𝑒𝑓𝑢𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 𝑜𝑢𝑡

𝑡𝑜𝑡𝑎𝑙 𝑒𝑛𝑒𝑟𝑔𝑦 𝑖𝑛(× 100%)

𝑒𝑓𝑓𝑖𝑐𝑖𝑒𝑛𝑐𝑦 =𝑢𝑠𝑒𝑓𝑢𝑙 𝑝𝑜𝑤𝑒𝑟 𝑜𝑢𝑡

𝑡𝑜𝑡𝑎𝑙 𝑝𝑜𝑤𝑒𝑟 𝑖𝑛 (× 100%)

Efficiency can be expressed as a percentage or a number less than 1. Complete this table.

% 67 23 15.6 7.1

Number 0.92 0.43 0.04 0.043

Complete this table by calculating the missing values. Give your answers to 1 or 2 decimal places.

Total energy in Useful energy out Efficiency

345 231

150 20

10 562 7%

943 35%

425 0.02

68 84%

Sankey diagrams can be used to represent the energy transformations that occur in a device or appliance.

Describe which of the device is most efficient, which is least efficient and explain how you can tell from the Sankey diagrams.

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Calculate the efficiencies of the appliances A, B and C.

Here is information on two types of low energy light bulb.

Type of bulb Efficiency Lifetime (hours) Cost of one bulb

Halogen 10% 2 000 £1.95

Compact Fluorescent Lamp (CFL) 20% 10 000 £3.10

Light Emitting Diode (LED) 32% 36 000 £11.70

Sketch and label a Sankey diagram for one on the light bulbs

Use the data in the table to evaluate the cost-effectiveness of the LED bulb compared to the other bulbs

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Suggest the benefits of developing brighter and more efficient LED chips

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What does the term ‘payback time’ mean?

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Physics 9 Cost We can calculate the cost of the electricity we use by using the following equation.

𝑇𝑜𝑡𝑎𝑙 𝑐𝑜𝑠𝑡 = 𝑛𝑢𝑚𝑏𝑒𝑟 𝑜𝑓 𝑢𝑛𝑖𝑡𝑠 × 𝑐𝑜𝑠𝑡 𝑝𝑒𝑟 𝑢𝑛𝑖𝑡

Which unit does the term ‘number of units’ refer to? _______________________________________________________________

Here are two electricity bills that a customer received. Explain how the number of units has been calculated.

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________________________________________________________________________________________________________ The diagrams show the reading on a domestic electricity meter in April and July

How many units of electricity we used between the two meter readings? Explain how you reached your answer.

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___________________________________________________ Calculate the cost of the electricity used if each unit costs 18p. ___________________________________________________ Here are the electricity bills for two households.

Calculate the cost of electricity for the two bills. A homeowner decides to monitor the amount of electrical energy used in his home. He can do this by using the home’s electricity meter or by using a separate electronic device. The table gives some information about each method.

What are the advantages of using the electronic device?

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Suggest how data collected and displayed by the electronic device could be usefully used by the homeowner

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Electricity meter Electronic device

Homeowner takes readings at regular Intervals

Energy use recorded continuously and stored for one year.

Generating Electricity

Physics 10 Non-Renewables ●In some power stations an energy source is used to heat water. The steam produced drives a turbine that is coupled to an electrical generator. Energy sources include:

■ the fossil fuels (coal, oil and gas) which are burned to heat water or air ■ uranium and plutonium, when energy from nuclear fission is used to heat water ■ biofuels that can be burned to heat water.

Physics 11 Renewables ●Water and wind can be used to drive turbines directly. Energy sources used in this way include, but are not limited to, wind, waves, tides and the falling of water in hydroelectric schemes. ●Electricity can be produced directly from the Sun’s radiation. Candidates should know that solar cells can be used to generate electricity and should be able to describe the advantages and disadvantages of their use. ●In some volcanic areas hot water and steam rise to the surface. The steam can be trapped and used to drive turbines. This is known as geothermal energy.

Physics 12 The National Grid ●Compare the advantages and disadvantages of overhead power lines and underground cables. ●Electricity is distributed from power stations to consumers along the National Grid. Candidates should be able to identify and label the essential parts of the National Grid. ●For a given power, increasing the voltage reduces the current required and this reduces the energy losses in the cables. Candidates should know why transformers are an essential part of the National Grid. ●The uses of step-up and step-down transformers in the National Grid. Details of the structure of a transformer and how a transformer works are not required.

Physics 13 Energy Issues ●Compare the advantages and disadvantages of using different electrical appliances for a particular application. Candidates will be required to compare different electrical appliances, using data provided. ●Consider the implications of instances when electricity is not available. ●Evaluate different methods of generating electricity. Candidates should be able to evaluate different methods of generating electricity given data including start-up times, costs of electricity generation and the total cost of generating electricity, when factors such as building and decommissioning are taken into account. The reliability of different methods should also be understood. Knowledge of the actual values of start-up times and why they are different is not needed, but the implications of such differences are important. ●Evaluate ways of matching supply with demand, either by increasing supply or decreasing demand. Candidates should be aware of the fact that, of the fossil fuel power stations, gas-fired have the shortest start-up time. They should also be aware of the advantages of pumped storage systems in order to meet peak demand, and as a means of storing energy for later use. ●Small-scale production of electricity may be useful in some areas and for some uses, eg hydroelectricity in remote areas and solar cells for roadside signs. Candidates should understand that while small-scale production can be locally useful it is sometimes uneconomic to connect such generation to the National Grid. ●Using different energy resources has different effects on the environment. These effects include:

■ the release of substances into the atmosphere ■ the production of waste materials ■ noise and visual pollution ■ the destruction of wildlife habitats.

●Candidates should understand that carbon capture and storage is a rapidly evolving technology. To prevent carbon dioxide building up in the atmosphere we can catch and store it. Some of the best natural containers are old oil and gas fields, such as those under the North Sea.

Physics 10 Non-Renewables What is meant by the term ‘non-renewable energy resource’?

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What are the three fossil fuels? _______________________________________________________________________________

Why are fossil fuels considered to by non-renewable energy resources?

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Here is a diagram of a power station that uses fossil fuels to produce electricity; add labels to it. Explain what happens in the power station to produce electricity, this can be done in bullet points.

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Describe the energy transformations that take place producing electricity in this way.

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How and where is energy lost in the production of electricity using this method?

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Electricity can also be generated by using nuclear power. Which fuels are most commonly used in nuclear power stations? ____________________________________________________

What happens to the fuel to produce heat? _____________________________________________________________________

What is the heat used to do? ________________________________________________________________________________

Nuclear fuels are a very concentrated energy resource compared to fossil fuels. What does this mean?

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Biofuels are not a non-renewable resource but are used in a similar way to fossil fuels. What are biofuels? Give some examples.

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Why are biofuels considered renewable energy resources?

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Biofuels are carbon neutral, what does this mean?

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Physics 11 Renewables

What is meant by the term ‘renewable energy resource’?

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Explain how each energy resource is used to turn a turbine.

Wind____________________________________________________________________________________________________

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Wave___________________________________________________________________________________________________

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Tidal____________________________________________________________________________________________________

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Hydroelectric_____________________________________________________________________________________________

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Geothermal______________________________________________________________________________________________

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________________________________________________________________________________________________________ What are the energy transformations that occur when electricity is generated using the hydroelectric method?

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________________________________________________________________________________________________________ The Sun’s radiation can be used in solar heating panels and solar cells attached to the roofs of buildings. Solar heating panels contain pipes carrying cold water; the radiation from the Sun heats the water to provide the home with warm water for bathing. Solar cells directly convert light energy into electrical energy which is connected to the home and the National Grid. Why are they also connected to the National Grid?

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Where else are solar cells used to generate electricity?

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Which type of areas or conditions would the following renewable energy resources used in?

Wind____________________________________________________________________________________________________

Wave___________________________________________________________________________________________________

Tidal____________________________________________________________________________________________________

Hydroelectric_____________________________________________________________________________________________

Geothermal______________________________________________________________________________________________

Physics 12 The National Grid

What is the main purpose of the National Grid?

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What is the National Grid?

A system of cables and pylons. A system of cables and transformers.

A system of cables, transformers and power stations.

Add labels to this diagram of the National Grid.

What happens at the power station (in terms of electricity)?_________________________________________________________

________________________________________________________________________________________________________

Step-up transformers ____________________________ the voltage and ____________________________ the current.

Why are step-up transformers used in the National Grid?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

Step-down transformers ____________________________ the voltage and ____________________________ the current.

Why are step-down transformers used in the National Grid?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

Cables can be suspended from pylons and run overhead or be buried underground. What are the advantages of using overhead power lines?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

What are the disadvantages of using overhead power lines?

________________________________________________________________________________________________________

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What are the advantages of using underground cables?

________________________________________________________________________________________________________

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What are the disadvantages of using underground cables?

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________________________________________________________________________________________________________ Before 1926, large towns had their own local power stations. After 1926, these power stations were connected to form the National Grid.What are the advantages of using electricity that is created locally?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

What are the advantages of having the National Grid in place?

________________________________________________________________________________________________________

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Physics 13 Energy Issues

Describe the impact that each energy resource has on the environment.

Fossil fuels_______________________________________________________________________________________________

________________________________________________________________________________________________________

Nuclear__________________________________________________________________________________________________

________________________________________________________________________________________________________

Biofuels_________________________________________________________________________________________________

________________________________________________________________________________________________________

Wind____________________________________________________________________________________________________

________________________________________________________________________________________________________

Wave___________________________________________________________________________________________________

________________________________________________________________________________________________________

Tidal____________________________________________________________________________________________________

________________________________________________________________________________________________________

Hydroelectric_____________________________________________________________________________________________

________________________________________________________________________________________________________

Solar____________________________________________________________________________________________________

Geothermal______________________________________________________________________________________________

When fossil fuels are burnt they produce carbon dioxide. Write the non-renewable energy resources in order of highest to longest carbon dioxide production.

________________________________________________________________________________________________________

What effect does carbon dioxide have on the environment?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

Other than burning less fossil fuels how could the amount of carbon dioxide that released into the environment be reduced?

________________________________________________________________________________________________________

________________________________________________________________________________________________________ Some fossil fuels contain sulphur impurities, when they are burnt they produce sulphur dioxide. What effect does sulphur dioxide have on the environment?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

In the UK, most electricity is generated in power stations that emit carbon dioxide into the atmosphere. The impact of these power stations on the environment could be reduced by the increased use of ‘carbon capture’ technology. Describe how ‘carbon capture’ would prevent the build-up of carbon dioxide in the atmosphere.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

________________________________________________________________________________________________________ What is meant by the term ‘reliable way of generating electricity’?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

State and explain how reliable each energy resource is.

Fossil fuels_______________________________________________________________________________________________

________________________________________________________________________________________________________

Nuclear__________________________________________________________________________________________________

________________________________________________________________________________________________________

Biofuels_________________________________________________________________________________________________

________________________________________________________________________________________________________

Wind____________________________________________________________________________________________________

________________________________________________________________________________________________________

Wave___________________________________________________________________________________________________

________________________________________________________________________________________________________

Tidal____________________________________________________________________________________________________

________________________________________________________________________________________________________

Hydroelectric_____________________________________________________________________________________________

________________________________________________________________________________________________________

Solar____________________________________________________________________________________________________

________________________________________________________________________________________________________

Geothermal______________________________________________________________________________________________

________________________________________________________________________________________________________ What is meant by the term ‘start-up time’ of an energy resource?

________________________________________________________________________________________________________

________________________________________________________________________________________________________ Write the non-renewable energy resources in order of shortest to longest start-up times.

________________________________________________________________________________________________________

What are the advantages of having a short start-up time?

________________________________________________________________________________________________________

________________________________________________________________________________________________________ It is important that the supply of electricity meets the demand for it. The demand for electricity in the UK, like all countries, varies over the day. The dotted line in the graph below is the base load of electricity, this is the constant amount of electricity generated and distributed by the National Grid per day. Which energy resources are likely to be used to supply the base load? Explain your answer.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

________________________________________________________________________________________________________

Think about the times of the day when our demand for electricity is high and the times when it is low. Sketch a graph to show how the power (or energy) used changes throughout the day.

Explain two of the features (high or low points) of the graph that you have sketched.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

________________________________________________________________________________________________________

A student suggests that the graph would look differently in summer compared to winter. Describe and explain the difference.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

________________________________________________________________________________________________________

Which energy resource or resources are likely to be used to add to the base load when demand is high?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

Other than developing and using energy resources how else could we ensure that supply meets demand?

________________________________________________________________________________________________________

________________________________________________________________________________________________________ Over the next 15 years, some of the older nuclear power stations will be closed down, and the process of decommissioning will start. What does it mean to decommission a nuclear power station?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

How does decommissioning affect the overall cost of electricity generated using nuclear fuels?

________________________________________________________________________________________________________

________________________________________________________________________________________________________ Read this extract from a newspaper.

Power crisis as island basks in sunshine The population of a small island off the coast of Scotland decided to generate all their electricity from water and wind. However, they did not predict having a long period or warm, dry weather. A combination of low water levels and hardly any wind has drastically reduced the output from the hydroelectric power station and wind turbines.

Explain one way in which the islanders could try to ensure that a similar power crisis does not happen in the future.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

________________________________________________________________________________________________________ The Sankey diagrams show the energy transfers in a traditional coal-burning power station and a combined heat and power (CHP) station. The CHP station uses heat generated from burning the fossil fuels to heat local homes, offices and factories.

Calculate the efficiency of the traditional power station.

Calculate the efficiency of the CHP station.

Why is a CHP station more efficient than a traditional coal-burning power station?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

Why is increasing the efficiency of power stations important?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

Waves

Physics 14 Properties of Waves ●Waves transfer energy. ●Waves may be either transverse or longitudinal. Candidates should understand that in a transverse wave the oscillations are perpendicular to the direction of energy transfer. In a longitudinal wave the oscillations are parallel to the direction of energy transfer. ●Electromagnetic waves are transverse, sound waves are longitudinal and mechanical waves may be either transverse or longitudinal. ●Longitudinal waves show areas of compression and rarefaction. ●The terms frequency, wavelength and amplitude. ●All waves obey the wave equation:

v = f x λ v is speed in metres per second, m/s f is frequency in hertz, Hz λ is wavelength in metres, m

Candidates are not required to recall the value of the speed of electromagnetic waves through a vacuum.

Physics 15 Refraction ●The normal is a construction line perpendicular to the reflecting surface at the point of incidence. ●Waves undergo a change of direction when they are refracted at an interface. Waves are not refracted if travelling along the normal. Snell’s law and the reason why waves are refracted are not required.

Physics 16 Reflection ●The angle of incidence is equal to the angle of reflection. ●The image produced in a plane mirror is virtual. Candidates will be expected to be able to construct ray diagrams.

Physics 17 Diffraction ●Waves can be reflected, refracted and diffracted. Candidates should appreciate that significant diffraction only occurs when the wavelength of the wave is of the same order of magnitude as the size of the gap or obstacle.

Physics 18 Sound ●Sound waves are longitudinal waves and cause vibrations in a medium, which are detected as sound. Sound is limited to human hearing and no details of the structure of the ear are required. ●The pitch of a sound is determined by its frequency and loudness by its amplitude. ●Echoes are reflections of sounds.

Physics 14 Properties of Waves

All waves transfer ______________________________________________

Waves are created by ______________________________________________________________________________________

There are two types of waves; transverse and longitudinal.

In a transverse wave the oscillations are _______________________________________ to the direction that the wave travels in.

In a longitudinal wave the oscillations are _______________________________________ to the direction that the wave travels in.

Examples of transverse waves are ____________________________________________________________________________

________________________________________________________________________________________________________

Examples of longitudinal waves are ___________________________________________________________________________

________________________________________________________________________________________________________

The diagram below is an example of a ____________________________________________ wave.

The diagram below is an example of a ____________________________________________ wave.

What do the following terms mean? Add them to the appropriate diagram above (if possible).

Peak ___________________________________________________________________________________________________

Trough __________________________________________________________________________________________________

Compression _____________________________________________________________________________________________

Rarefaction ______________________________________________________________________________________________

Wavelength ______________________________________________________________________________________________

Amplitude _______________________________________________________________________________________________

Frequency _______________________________________________________________________________________________

Wave speed _____________________________________________________________________________________________

𝑣 = 𝑓 × 𝜆

Symbol Quantity Units Unit Symbol

v

f

λ

Rearrange the equation to make f and then λ the subject. Complete this table by calculating the missing values.

v f λ

3 1.2

8 0.015

336 0.8

40 0.8

340 850

300 000 000 500 000 000 The diagram shows waves being produced on a rope. The waves are not reflected by the wall.

Draw an arrow on the diagram to show the direction in which the waves transfer energy. Which of the labelled arrows show the:

Amplitude? __________

Wavelength? __________ State which type of wave is shown in the diagram and explain how you can tell?

________________________________________________________________________________________________________

________________________________________________________________________________________________________ The diagram shows two ways in which a wave can travel along a slinky spring. Clearly indicate and label the wavelength of Wave A and Wave B Which a longitudinal wave? _______ Which is a transverse wave? _______

Physics 15 Refraction Explain what the word refraction means.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

A student investigated the refraction of light as it passed out of a clear plastic block into the air. The diagram shows the apparatus the student used.

What name is given to the dashed line? ____________________________

The angle i is the ______________________________________________

Use the letter r to mark the angle of refraction on the diagram.

Which piece of equipment would you use to measure the angles?

____________________________________________________________

Why doesn’t the light ray bend when it enters the plastic block?

____________________________________________________________

Why does the light ray bend when it travels from the plastic block to the air?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

The two diagrams, A and B, show a light ray travelling into a glass block.

Complete the diagrams to show the paths that the light rays take as they enter and then leave the glass block.

In diagram A, when the light ray travels from air to glass it will bend _________________________________________ the normal.

In diagram A, when the light ray travels from glass to air it will bend _________________________________________ the normal.

Physics 16 Reflection When dealing with light and mirrors it is important to use the correct vocabulary. Explain what the following words mean when used to describe an image produced through a lens.

Inverted _________________________________________________________________________________________________

Upright __________________________________________________________________________________________________

Magnified ________________________________________________________________________________________________

Diminished ______________________________________________________________________________________________

Real ____________________________________________________________________________________________________

Virtual __________________________________________________________________________________________________

The diagram shows a ray of light from a ray box that is reflected by a plane mirror. What name is given to the dashed line labelled as J?

_________________________________________________________

What is the name given to K?

_________________________________________________________

What is the name given to L?

_________________________________________________________

If K was doubled what would happen to L?

________________________________________________________

If K was halved what would happen to L?

________________________________________________________

A student looking into the mirror can see an image of the ray box. Which words from the list at the top of this page can be used to describe the image that the student sees?

________________________________________________________________________________________________________

What is the law of reflection?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

The diagram shows a model used to demonstrate an illusion known as ‘Pepper’s Ghost’. A small light bulb and thin sheet of glass are put inside a box. The thin sheet of glass acts as a mirror. Although the light bulb is switched on, a student looking into the box cannot see the bulb. What the student does see is a virtual image of the bulb.

Use a ruler to complete a ray diagram to show how the image of the light bulb is formed. Mark and label the position of the image.

The image seen by the student is virtual. Why?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

Physics 17 Diffraction Explain what the word diffraction means.

________________________________________________________________________________________________________

________________________________________________________________________________________________________ The diagrams show water waves in a ripple tank moving towards a gap in a barrier. The water waves diffract as they pass through the gap. Complete the diagrams to show the diffracted water waves.

Diffraction happens the most when the wavelength of the wave is ____________________________________________________

________________________________________________________________________________________________________

Terrestrial television does not use satellites. Terrestrial television signals and radio signals both use radio waves. Radio signals are transmitted at a longer wavelength than terrestrial television signals.

In hilly areas it may be possible to receive radio signals but not receive terrestrial television signals. Explain why.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

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Physics 18 Sound How are sounds produced?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

How do drums produce sound? _____________________________________________________________________________

How to guitars produce sound? _____________________________________________________________________________

How do flutes produce sound? _____________________________________________________________________________ Sound waves are longitudinal waves; use the diagram of a longitudinal wave to explain how sound waves travel from a speaker to an ear.

________________________________________________________________________________________________________

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________________________________________________________________________________________________________

What is a vacuum?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

Explain why sound waves cannot travel through a vacuum.

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The diagram shows the apparatus a teacher uses to demonstrate that sound can be reflected.

Using a ruler, draw on the diagram to show how sound from the loudspeaker is reflected by the sheet of metal to the sound sensor.

What is the name given to the reflection of a sound? ______________________________________________________________

The teacher replaced the sheet of metal with a sheet of glass. When he did this, the reading on the sound level meter went down. Suggest why.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

The amplitude of a wave determines the ___________________________________________ of a wave.

The frequency of a wave determines the ___________________________________________ of a wave.

If a microphone is connected to an oscilloscope it will display the waveforms of different sounds like in the diagrams below

Which of the waveforms has the largest amplitude? _______ Which of the waveforms has the smallest amplitude? _______

Which of the waveforms has the highest frequency? _______ Which of the waveforms has the lowest frequency? _______ How would the sound that made waveform B be like compared to the sound that made waveform D?

________________________________________________________________________________________________________

How would the sound that made waveform C be like compared to the sound that made waveform A?

________________________________________________________________________________________________________ The diagrams show oscilloscope traces for the same musical note played on two different instruments. The oscilloscope settings are not changed.

How can you tell, from the diagrams, that it is the same musical note?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

How can you tell, from the diagrams, that the musical note has been played on different instruments?

________________________________________________________________________________________________________

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The Electromagnetic Spectrum and Space

Physics 19 The EM Spectrum ●Compare the use of different types of waves for communication. Knowledge and understanding of waves used for communication is limited to sound, light, microwaves, radio waves and infrared waves. ●Evaluate the possible risks involving the use of mobile phones ●All types of electromagnetic waves travel at the same speed through a vacuum (space). ●Electromagnetic waves form a continuous spectrum. Candidates should know the order of electromagnetic waves within the spectrum, in terms of energy, frequency and wavelength. Candidates should appreciate that the wavelengths vary from about 10–15 metres to more than 104 metres. ●Radio waves, microwaves, infra red and visible light can be used for communication. Candidates will be expected to be familiar with situations in which such waves are typically used and any associated hazards, eg:

■ radio waves – television, and radio (including diffraction effects) ■ microwaves – mobile phones and satellite television ■ infra red – remote controls ■ visible light – photography.

Physics 20 Red Shift ●If a wave source is moving relative to an observer there will be a change in the observed wavelength and frequency. This is known as the Doppler Effect. The following should be included:

■ the wave source could be light, sound or microwaves ■ when the source moves away from the observer, the observed wavelength increases and the frequency decreases ■ when the source moves towards the observer, the observed wavelength decreases and the frequency increases.

●There is an observed increase in the wavelength of light from most distant galaxies. The further away the galaxies are, the faster they are moving, and the bigger the observed increase in wavelength. This effect is called red-shift. ●How the observed red-shift provides evidence that the universe is expanding and supports the ‘Big Bang’ theory (that the universe began from a very small initial point).

Physics 21 The Big Bang and CMBR ●Consider the limitations of the model that scientists use to explain how the universe began and why the universe continues to expand. ●Cosmic microwave background radiation (CMBR) is a form of electromagnetic radiation filling the universe. It comes from radiation that was present shortly after the beginning of the universe. ●The ‘Big Bang’ theory is currently the only theory that can explain the existence of CMBR.

Physics 19 The EM Spectrum

All electromagnetic waves transfer energy but do not transfer ________________________________________

Complete the table by writing the initials of the waves of the EM spectrum and colours of the visible section into the correct boxes.

X Visible Light

R G Y

As we go from left to right in the table above the wavelength of the waves ___________________________________________

As we go from left to right in the table above the frequency of the waves ___________________________________________

As we go from left to right in the table above the energy of the waves ___________________________________________

As we go from left to right in the table above the speed of the waves ___________________________________________

Circle the correct values for the range of wavelengths of the electromagnetic spectrum.

The longest EM wavelength is around The shortest EM wavelength is around

1015m 104m 10m 10-6 m 106m 10m 10-4m 10-15m

Complete this table by calculating the missing values. Give your answers to 2 decimal place.

EM Wave Frequency (Hz) Wavelength (m)

Infrared 3.2 x 1013

Radio Waves 2.5 x 102

Microwaves 1.8 x 109

Use EM Wave Use EM Wave

Sending a text from a mobile phone

To sterilise surgical equipment

Taking a photograph of a tree

A medical tracer injected into a patient

Killing cancerous cells inside a patient

Security ink used to mark your property

Turning off a television with a remote control

Producing shadow images of bones

Broadcasting a movie by satellite

Broadcasting a local radio show

In sunbeds to give a sun tan

Turning a piece of bread into toast

Taking a thermal photograph of a human

Cooking food in a microwave oven

What are the possible risks involved to human health in using a mobile phone?

________________________________________________________________________________________________________

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Physics 20 Red Shift The Doppler Effect can happen in sound, light or microwaves. In the diagram below an ambulance (with the siren turned on)is stationary between two people.

What would it sound like at A compared to B? Explain your answer in terms of frequency and wavelength.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

In this diagram the ambulance is now moving to the left, towards A and away from B.

What would the sound be like at A compared to B? Explain your answer in terms of frequency and wavelength.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

In the diagram below the light from a stationary galaxy is being observed by two people.

How would the light appear when observed from A compared from B? Explain your answer in terms of frequency and wavelength.

________________________________________________________________________________________________________

________________________________________________________________________________________________________

Now the galaxy is moving to the left, towards A and away from B.

How would the light appear when observed from A compared from B? Explain your answer in terms of frequency and wavelength.

________________________________________________________________________________________________________

________________________________________________________________________________________________________ Scientists use radio telescopes to measure the wavelength of the radio waves emitted from galaxies as the waves reach the Earth. They often measure an increase in wavelength; the effect causing this observed increase in wavelength is called red-shift.

The waves emitted from most galaxies show red-shift; what does this tell scientists about the direction most galaxies are moving?

________________________________________________________________________________________________________

What does the observation of red-shift suggest is happening to the Universe?

________________________________________________________________________________________________________

The size of the red-shift is not the same for all galaxies. Scientists can conclude information about a galaxy when they measure the size of the red-shift the galaxy produces.

The bigger the red-shift 1___________________________________________________________________________________

2 ___________________________________________________________________________________ The visible spectrum from stars includes dark lines; these lines are at specific wavelengths. The diagram shows the position of

three dark lines in the spectrum from the Sun. The same lines are also present in Star A and Star B.

Which star is moving towards Earth? _______________________

How do you know? _____________________________________

____________________________________________________

Which star is moving away from Earth? ____________________

How do you know? _____________________________________

____________________________________________________

Physics 21 The Big Bang and CMBR Most scientists support a theory that the Universe began from a very small initial point. Red-shift can be used as evidence for this theory. What name is given to the theory that the Universe began from a very small initial point?

________________________________________________________________________________________________________

Which statement gives the reason why most scientists support the theory that the Universe began from a very small initial point?

The evidence proves it happened.

There is no other way of explaining how the Universe began.

At the moment it is the best way of explaining our scientific knowledge.

Observations help scientists answer questions about the Universe. Scientists cannot answer every question. Which one of the following questions cannot be answered by scientists?

How old is the Universe? Why was the Universe created? How fast does light travel through the Universe?

Which one of the following statements gives the main reason why models are used in science?

Models can help to explain an effect or theory.

Models can prove that a theory is correct.

Models can prove that a theory is wrong.

Cosmic microwave background radiation (CMBR) is a type of electromagnetic radiation. It was first discovered in 1965 by two astronomers called Penzias and Wilson. Where does CMBR come from?

CMBR only comes from near the Sun.

CMBR comes from all parts of the Universe.

CMBR only comes from the Moon.

What do scientists believe is the origin of CMBR?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

Why was the discovery of CMBR so important to the scientists believing the ‘Big Bang’ theory to be correct?

________________________________________________________________________________________________________

________________________________________________________________________________________________________

How is the wavelength of CMBR likely to change, if at all, over the next billion years? Explain your answer.

________________________________________________________________________________________________________

________________________________________________________________________________________________________