1. P1 Exam Questions

2. The following presentation has examples of the AQA P1 questions that have been in the past exams. The order of the questions is roughly in the order that they have been in in the exams. If you learn the answers to these 40 questions and can apply them to similar questions you will do really well in the exam!

3. 1.Types of energy and how they are transformed as useful and wasted energy Magnetic - MagnetEnergy in magnets and electromagnets Kinetic - A bullet cutting a playing cardThe energy in moving objects. Also called movement energy. Heat - Burning matchAlso called thermal energy Light - SunlightAlso called radiant energy Gravitational potential - Sky diversStored energy in raised objects Chemical - Organic foodStored energy in fuel, foods and batteries Sound - GuitarEnergy released by vibrating objects Electrical - LightningEnergy in moving or static electric charges Elastic potential - CatapultStored energy in stretched or squashed objects Nuclear - Nuclear fuel assemblyStored in the nuclei of atoms

4. 1.Types of energy and how they are transformed as useful and wasted energy e.g. A cyclist loses as they travel down a hill and gains. As they apply the brakes this energy is changes into as the bike stops. GRAVITATIONAL POTENTIAL ENERGY KINETIC ENERGY HEAT/THERMAL ENERGY

5. 2. Must be able to calculate energy transferred as Energy (kW hours) = power (kW) x time (hours) How much energy does a kettle use each day if it is on for 30 minutes and has a power rating of 2000W? Power = 2kW Time = 0.5 hours Energy = 2kW x 0.5 hours Energy (number of units) = 1 kiloWatt hour

6. 3. Must be able to calculate cost of electricity by multiplying number of kW hours by cost per kWh Energy used (kW hours) Unit cost (pence) Cost of using appliance (£) 510 16.58 1914 12 Calculate the cost in pounds of these appliances on different electrical tariffs: 0.5 1.32 2.66 1.44

7. 4. Define the Watt. Power (W) = Energy (J) / time (s) 1 W = 1 J / 1 s So 1 Watt is 1 Joule per second

8. 5. How many watts are in 1kW? kilo means x1000 So 1kW = 1000W

9. 6. Calculate efficiency from the Sankey diagram below Efficiency = useful output energy (J) total input energy (J) This will give a number between 0 and 1 and you can give your answer like this with no unit. Sometimes the exam will ask you to give your answer as a percentage, if so you must x100%

10. 6. Calculate efficiency from the Sankey diagram below Efficiency = useful output energy (J) total input energy (J) Useful output energy = 6 squares Total input energy = 20 squares Efficiency = 6/20 Efficiency = 0.3 Or could be written as Efficiency = 30%

11. 7. Calculate the efficiency from data given. An energy efficient lightbulb transforms 20J of electrical energy into 4J of light energy every second. Calculate the efficiency of the bulb. Efficiency = useful output energy (J) total input energy (J) Efficiency = 4/20 Efficiency = 0.2 Or could be written as 20%

12. 8. Must be able to compare the efficiencies of things using Sankey diagrams Compare the efficiencies of these lights: The bottom Sankey diagram shows a light that is more efficient than the top one (1 mark) Since more of the total energy is transformed into useful (light) energy. (2 marks) 3 rd /4 th mark for comparison using data The efficiency from the top diagram is 10% The efficiency from the bottom diagram is 75%

13. 9. Must be able to compare the cost efficiency of different appliances from data given in tables Use the data in the table to evaluate the cost-effectiveness of an LED bulb compared to a CFL. (2 marks)

14. 9. Must be able to compare the cost efficiency of different appliances from data given in tables

15. 10. Must be able to state advantages and disadvantages of different power stations Describe the features of electrical production of the following and the advantages and disadvantages of each one:

16. Solar Energy – energy from the Sun + Renewable + No pollution, because nothing gets burned – Solar cells and solar panels are expensive – Only works if it’s sunny! The Earth gets heat and light energy from the sun all the time. Can we use it – yes we can! The Sun’s energy can either be: 1.changed into electrical energy to use in homes, using solar cells; 2.or used to heat water for homes, using solar panels.

17. Wind Energy – energy from the wind + Renewable + No pollution, because nothing gets burned + Turbines are quite cheap and easy to build, so they can be used even in poor countries – Turbines can be ugly and noisy – Only works if it’s quite windy! If the wind stops, you get no energy. Using wind turbines, we can turn the kinetic energy of the wind into electrical energy which we can use in our homes. This is ‘wind energy’.

18. Biomass Energy – energy from plants 1.Trees absorb the sun’s energy. The trees change this energy into chemical energy, which they store inside themselves. 2.When we burn wood, we turn this energy into heat, which is useful for cooking and heating. + Renewable – as long as we keep planting trees to replace the ones we cut down + Doesn’t need any special equipment, so it can be used very easily, even in poor countries + Doesn’t add to the greenhouse effect – Large areas of land are needed to grow enough trees The chemical potential energy stored in things that were once alive (e.g. trees) can be turned into heat energy by burning them. (We can also turn it into electrical energy to use in our homes.)

19. Geothermal Energy – energy from the Earth 1.Cold water is pumped below the ground. 2.Hot rocks heat the water, turning it into steam. 3.The steam is used to generate electricity. + Renewable + No pollution, because nothing gets burned + Doesn’t damage the environment – Very few places in the world where you can do this – Costs a lot of money to drill deep into the ground Deep underground, the Earth’s rocks are naturally very hot. We can turn their heat energy into electrical energy to use in our homes – we call this ‘geothermal energy’.

20. Hydroelectric Energy – energy from rivers + Renewable + No pollution, because nothing gets burned + We can store the water up high, and then whenever we need the energy we can let the water out The water flowing in a river has kinetic energy. We can turn this into electrical energy to use in our homes. We usually need to build a dam, and let the water flow through it gradually. – Costs a lot of money to build a dam – The dam can ruin the local environment, because it changes where the water naturally flows. Some animals and plants may die.

21. Tidal Energy – energy from sea tides 1.At high tide, we trap the water behind a dam. 2.At low tide, the water is released, and its energy is used to generate electricity. + Renewable + No pollution, because nothing gets burned + Reliable, because there are always two tides every day + Cheap to run, once it’s built – Costs a lot to build the dam – The dam may cause local flooding If you’ve ever been to the coast, you may have noticed that the sea level goes up and down, because of tides. When the tide is high, the water has lots of gravitational potential energy, which we can turn into electrical energy to use in our homes.

22. Wave Energy – energy from sea waves + Renewable + No pollution, because nothing gets burned The sea’s waves have kinetic energy. Using machines that bob up and down in the waves, this energy can be turned into electrical energy which we can use in our homes. – Need lots of machines to get a reasonable amount of energy – The machines costs a lot of money – The machines can look ugly – The machines can be damaged by storms wave energy machines bobbing up and down in the waves

23. 11. Must be able describe how demand for electricity is met at different times by different types of power station Demand for electricity varies over a 24 hour period and also over the whole year. The base load must cover the minimum demand over the time period. There are increases and peaks that need to be met. These are met by power stations that can be turned on and off quickly – the start up time tells you this.

24. 11. Must be able describe how demand for electricity is met at different times by different types of power station Which power stations are used to cover the base load of electricity usage? The base load is covered by fossil fuel power stations and nuclear power stations as they are very reliable but slow to increase or reduce the amount of electrical energy supplied. If there is a sudden peak in electricity demand explain which power stations could be used to match this need. Gas and hydroelectric power stations have small start up times and are used in times of peak demand

25. 12. Must be able to describe conduction in non-metals Describe conduction in non-metals. Conduction is the transfer of heat through solids Heat energy gives particles kinetic energy so they vibrate quicker/more This kinetic energy is transferred from particle to particle By collisions between the particles Conduction occurs quickest in solids that are more dense as the particles are closer together

26. 13. Must be able to describe conduction in metals Describe conduction in non-metals. Conduction is the transfer of heat through solids Heat energy gives particles and free electrons kinetic energy so they vibrate quicker/more This kinetic energy is transferred from particle to particle and electron to electron By collisions between the particles and electrons Conduction occurs quickest in metals that have the most free electrons

27. 14. Must be able to describe convection Describe how heat is transferred in convection. Convection occurs in fluids Heat energy makes particles spread apart This makes the fluid less dense And so the fluid rises As the fluid cools it gets more dense and the particles become closer together and so they sink

28. 15. Must be able to describe how cooling systems work Radiation is the transfer of heat by infrared waves Dark/black/matt objects absorb the most infra-red and also emit the most infrared Light/white/shiny objects reflect infrared the most and also absorb the least Objects with a large surface area emit the most infrared

29. 15. Must be able to describe how cooling systems work Describe how cooling fins in a computer work The cooling fins are black and so emit the most amount of infrared Also there are lots of fins to give a large surface area to emit the most amount of infrared possible.

30. 16. Must be able to describe how Infrared can be used for grilling How is food cooked by a grill (or toaster or an oven)? A grill/toaster/oven heats food with infrared radiation The infrared is absorbed by the surface of the food The rest of the food is cooked by conduction

31. 17. Must be able to describe how light- coloured shiny objects reflect infrared Explain why marathon runners are given a shiny blanket after they have finished the run Light/silver/shiny materials are good reflectors and bad absorbers of infrared radiation So heat from the runner is reflected back towards the runner Ensuring that they stay warm

32. 18. Must be able to describe how condensation occurs Why does a mirror in a bathroom steam up when the shower is running? water evaporates water molecules / particles go into the air mirror is cooler than air water molecules / particles that hit the mirror lose energy causes condensation on the mirror

33. 19. Must describe evaporation and how it can cool objects down Evaporation occurs when particles in a liquid have enough kinetic energy to escape the liquid These particles become particles in a gas

34. 19. Must describe evaporation and how it can cool objects down Describe how evaporation occurs in a puddle of water on a warm day and explain what happens to the temperature of the puddle. Particles with enough kinetic energy escape From the surface of the puddle And become particles of a gas Because these particles had the most kinetic energy the average kinetic energy of the particles in the puddle goes down This means that the overall temperature of the puddle goes down

35. 20. Must be able to describe kinetic theory Describe the difference in terms of the energy particles have in solids, liquids and gases. Use diagrams to aid your explanation. Particles in a solid have the least amount of kinetic energy And so the bonds between the particles allow them only to vibrate about fixed positions Particles in a liquid have more kinetic energy And so bonds between particles break The attraction between particles means that they are still touching but can flow in between each other Particles in a gas have the most kinetic energy Particles do not have bonds between them So can move freely between each other

36. 21. Must be able to calculate payback time Payback time is the time it takes to pay back the cost of insulation from the saving made each year. Payback time = cost of insulation. savings made each year Double glazing costs £2000 to install in a house and saves £250 each year in heating bills. What is the payback time? Payback time = 2000/250 Payback time = 8 years

37. 22. Must be able to compare insulators using U-Values What is a U-Value? A U-value compares the rate of energy loss per square metre of an insulator. It is a way to compare the effectiveness of insulators How does the U-Value change depending on the insulator? The better the insulator the lower the U-Value

38. 23. Must be able to calculate specific heat capacity Specific heat capacity is the amount of energy required to raise a kg of a material by 1 degree Celsius. The equation is: E = m x c x T Energy = mass x s.h.c. x temperature change

39. 23. Must be able to calculate specific heat capacity a A 1 kg block of Compound A is heated, increasing its temperature by 1  C. How much energy has been added to the block? b How much energy is needed to increase the temperature of 1kg of water by 10  C? 4,180 J / kg  C c10,000 J is added to 1kg of water. How much does the water temperature increase by? Compound A s.h.c = 5000 J/Kg/°C 5000J 41800J 2.39°C

40. 24. Must be able to describe properties of all EM waves Properties of EM waves: travel (at same speed) through a vacuum / space transverse transfer energy can be reflected can be refracted can be diffracted can be absorbed travel in straight lines

41. 24. Must be able to describe properties of all EM waves State 2 properties that all electromagnetic waves share travel (at same speed) through a vacuum / space transverse

42. 25. Must be able to compare frequency and wavelength of EM waves Randy – Radio – Longest wavelength, smallest frequency Monkeys - Microwave In - Infrared Velvet - Visible Underpants - Ultraviolet Xterminate – X-Rays Gibbons – Gamma rays – smallest wavelength, highest frequency

43. 25. Must be able to compare frequency and wavelength of EM waves Which has the highest frequency – infrared or ultraviolet waves? Ultraviolet Which has the largest wavelength – visible waves or microwaves? Microwaves

44. 26. Must be able to describe reflection and draw diagrams Draw a labelled ray diagram to show how light reflects from a plane mirror

45. 27. Must be able to draw ray diagrams to find an image in a plane mirror Draw a ray diagram to show where the image of the object would appear in the mirror

46. 28. Must be able to define a virtual image Define what is meant by a virtual image A virtual image is one that cannot be projected

47. 29. Must be able to describe refraction and draw diagrams What is refraction? Draw a labelled ray diagram to show how light refracts from air through a glass block Refraction is the change of direction of a wave when it enters a medium where its speed is different. The refraction of light when it passes from a fast medium to a slow medium bends the light ray toward the normal to the boundary between the two media.

48. 30. Must be able to describe diffraction and how communications may be affected in valleys What is diffraction? Diffraction is the spreading out of waves as they pass through a hole or around an object Maximum diffraction occurs when the wavelength is a similar size to that of the hole

49. 30. Must be able to describe diffraction and how communications may be affected in valleys Using a diagram to help explain it why can radio signals be picked up in a valley but television signals cannot always. Radio waves have a longer wavelength and bend more than waves for television.

50. 31. Must be able to describe how radio waves are used to communicate Use a diagram to help explain how radio waves can be used to communicate large distances

51. 32. Must be able to describe how microwaves are used to communicate Use a diagram to explain how microwaves can be used to communicate large distances (why can’t radio waves be used in this way?) Microwaves have the property that they can pass through the ionosphere whereas radio waves get reflected by it. They travel to satellites that pass on the signal

52. 34. Must be able to describe what frequency is Define frequency Frequency is the number of waves in a second f = 1/T

53. 34. Must be able to use the wave equation v = f x λ Calculate the speed of a wave that has a frequency of 50 Hz and a wavelength of 4 m. 200 m/s Calculate the speed of a wave that has a frequency of 5 kHz and a wavelength of 4 m 20 000 m/s Calculate the frequency of a sound wave of speed 330 m/s and wavelength 110 m. 3Hz

54. 35. Must be able to compare CRO displays of waves and describe amplitude, wavelength and frequency Which wave – A or B – has the: Largest wavelength: B Largest frequency: A Smallest amplitude: B Which wave is most likely to be: A referee’s whistle: A A quiet note from a base guitar: B A B

55. 36. Describe the difference between a transverse and a longitudinal wave In transverse waves, the vibrations are at right angles to the direction of travel. In longitudinal waves, the vibrations are along the same direction as the direction of travel.

56. 37. Must be able to describe what the Doppler effect is What is the Doppler effect? When a source moves towards an observer, the observed wavelength decreases and the frequency increases. When a source moves away from an observer, the observed wavelength increases and the frequency decreases.

57. 38. Must be able to state what the Big Bang theory is What is the Big Bang Theory? The theory states that about 13.6 billion years ago all the matter in the Universe was concentrated into a single incredibly tiny point. This began to enlarge rapidly in a hot explosion, and it is still expanding today.

58. 39. Must be able to explain how Redshift is evidence for the Big Bang theory 40. Must be able to explain how CMBR is evidence for the Big Bang Theory Explain what evidence there is for the Big Bang Theory. There are 2 main pieces of evidence for the Big Bang theory: 1Redshift All the Galaxies are Red Shifted (their spectra are shifted towards the red end of the spectrum) This means that all the galaxies are moving away from us 2CMBR The early universe was very hot and had very high frequency waves. Over the last 13.6 billion years these waves have been stretched out to become microwaves which we detect as the Cosmic Microwave Background Radiation