The Sankey diagram is for a 30 W light bulb over a period of time. Calculate the energy wasted by the light bulb in this period of time....

Transcription

1 Q1. A student finds some information about energy-saving light bulbs. (a) The Sankey diagram is for a 30 W light bulb over a period of time. Calculate the energy wasted by the light bulb in this period of time.. Wasted energy =... J What happens to the energy wasted by the light bulb?.. (iii) Calculate the efficiency of this light bulb. Use the correct equation from Section C of the Physics Equations Sheet... Efficiency =... (iv) Calculate the period of time, in seconds, during which the 600 J is provided to the 30 W light bulb. Use the correct equation from Section C of the Physics Equations Sheet... Time =... s Page 1 of 32

2 (b) A company that makes light bulbs provides information about some of their products. The table shows some of this information. Power in watts Lifetime in hours Cost of bulb in Filament bulb LED bulb Suggest why it is important to confirm this information independently.. A homeowner is thinking about replacing his filament bulbs with LED bulbs. A 12 W LED bulb gives the same light output as a 60 W filament bulb. Suggest reasons why the homeowner is likely to choose LED bulbs. Use the information given in the table..... (iii) State one factor, other than efficiency, that is important when considering the choice of a bulb for lighting in the home... (Total 10 marks) Page 2 of 32

3 Q2. The bar chart shows the different energy sources used to generate the UK s electricity in (a) The wind is a renewable energy source. Name one more renewable energy source used to generate electricity.... Complete the following sentence by drawing a ring around the correct line in the box. decrease Using less fossil fuels to generate electricity will not change the increase amount of carbon dioxide emitted into the atmosphere. (b) The graph shows how the demand for electricity in the UK varied over one day in the winter. Page 3 of 32

4 Describe how the demand for electricity varied between 4.00 am and am Which type of power station has the fastest start-up time? Draw a ring around your answer. coal natural gas nuclear oil (Total 5 marks) Q3. Different parts of the electromagnetic spectrum have different uses. (a) The diagram shows the electromagnetic spectrum. Radio waves Microwaves Infrared Visible light Ultraviolet X-rays Gamma rays Use the correct answers from the box to complete the sentence. amplitude frequency speed wavelength The arrow in the diagram is in the direction of increasing... and decreasing.... Draw a ring around the correct answer to complete the sentence. The range of wavelengths for waves in the electromagnetic to 10 4 spectrum is approximately 10-4 to to metres. Page 4 of 32

5 (b) The wavelength of a radio wave is 1500 m. The speed of radio waves is m / s. Calculate the frequency of the radio wave. Use the correct equation from Section B of the Physics Equations Sheet. Give the unit Frequency =... (3) (c) State one hazard of exposure to infrared radiation.. State one hazard of exposure to ultraviolet radiation.. (d) X-rays are used in hospitals for computed tomography (CT) scans. State one other medical use for X-rays... State a property of X-rays that makes them suitable for your answer in part (d)... (iii) The scientific unit of measurement used to measure the dose received from radiations, such as X-rays or background radiation, is the millisievert (msv). The table shows the X-ray dose resulting from CT scans of various parts of the body. The table also shows the time it would take to get the same dose from background radiation. Page 5 of 32

6 Part of the body X-ray dose in msv Time it would take to get the same dose from background radiation Abdomen years Sinuses months Spine months A student suggests that the X-ray dose and the time it would take to get the same dose from background radiation are directly proportional. Use calculations to test this suggestion and state your conclusion (3) (Total 13 marks) Page 6 of 32

7 Q4. (a) The diagram shows how much heat is lost each second from different parts of an uninsulated house. Each year, the house costs 760 to heat. How much money is being wasted because of heat lost through the roof? Show clearly how you work out your answer Insulating the loft would cut the heat lost through the roof by 50 %. The loft insulation has a payback time of years. How much did the loft insulation cost to buy?... Cost of loft insulation =... (b) What happens to the wasted energy? (Total 4 marks) Page 7 of 32

8 Q5. The diagram shows a metal pan being used to heat water. Energy from the gas flame is transferred through the metal pan by conduction. Explain the process of conduction through metals (4) (Total 4 marks) Q6. The diagram below shows an electric kettle and the label on the bottom of the kettle. The water at the bottom of the kettle will heat up first. This is because the heating element is near the bottom of the kettle. Convection currents will then cause the rest of the water in the kettle to be heated. What are convection currents?... Page 8 of 32

9 Explain how convection currents are produced. (Your answer should refer to density and temperature.) (4) (Total 5 marks) Q7. (a) Figure 1 shows a signal generator connected to a loudspeaker. The signal generator is adjusted to change the sound wave produced by the loudspeaker. Figure 1 A microphone connected to a cathode ray oscilloscope (CRO) is used to detect the sound waves from the loudspeaker. Figure 2 shows the CRO traces, A, B and C, produced by three different sound waves. The settings on the CRO were the same for each trace. Figure 2 A B C Use the correct letter, A, B or C, to complete each sentence. The sound wave with the highest frequency is shown by trace. Page 9 of 32

10 The sound wave with the smallest amplitude is shown by trace. (b) The loudspeaker produces a sound wave with a frequency of 850 hertz and a wavelength of 0.4 metres. Calculate the speed of this sound wave. Give the unit. Use the correct equation from the Physics Equations Sheet. Choose the unit from the list below. joules metres / second watts Speed =... (3) (c) A motorbike is driven towards a microphone and CRO which are placed by the side of the road. The motorbike emits a sound wave of constant frequency. Draw a ring around the correct answer to complete each sentence. As the motorbike moves towards the microphone, the frequency of the sound wave higher than detected by the microphone will be the same as the frequency of the sound wave lower than produced by the motorbike. The wavelength of the sound wave detected by the microphone will be the wavelength of the sound wave from the motorbike. longer than the same as shorter than (Total 7 marks) Page 10 of 32

11 Q8. The big bang theory is one theory explaining the origin of the Universe. (a) The graphs X, Y and Z, show how the size of the Universe may have changed with time. Which graph would the big bang theory suggest is correct? Write your answer, X, Y or Z, in the box. Explain the reason for your answer (3) (b) In 1948, an alternative to the big bang theory, called the steady state theory, was developed. The steady state theory suggested that the Universe, although expanding, has always existed without a beginning in time. Complete the following sentence by drawing a ring around the correct line in the box. The measurement of red-shift in the light from distant galaxies provides evidence only the big bang theory. to support only the steady state theory. both the big bang and steady state theories. Page 11 of 32

12 In 1965, scientists rejected the steady stat theory in favour of the big bang theory. Suggest what might cause scientists to stop supporting one theory and to start supporting an alternative theory. (Total 5 marks) Q9. Diagram 1 shows the energy transferred per second from a badly insulated house on a cold day in winter. Diagram 1 (a) When the inside of the house is at a constant temperature, the energy transferred from the heating system to the inside of the house equals the energy transferred from the house to the outside. Calculate, in kilowatts, the power of the heating system used to keep the inside of the house in Diagram 1 at a constant temperature. 1 kilowatt (kw) = 1 kilojoule per second (kj/s) Power of the heating system =... kw Page 12 of 32

13 In the winter, the heating system is switched on for a total of 7 hours each day. Calculate, in kilowatt-hours, the energy transferred each day from the heating system to the inside of the house. Use the correct equation from the Physics Equations Sheet. Energy transferred each day =... kwh (iii) Energy costs 15 p per kilowatt-hour. Calculate the cost of heating the house for one day. Cost =... (iv) The heating system is switched off at midnight. The graph shows how the temperature inside the house changes after the heating system has been switched off. Time of day Draw a ring around the correct answer in the box to complete the sentence. Between midnight and 6 am the rate of energy transfer from decreases. the house decreases then stays constant. increases. Give the reason for your answer. Page 13 of 32

14 (b) Diagram 2 shows how the walls of the house are constructed. Diagram 3 shows how the insulation of the house could be improved by filling the air gap between the two brick walls with plastic foam. Diagram 2 Diagram 3 U-value of the wall = 0.7 U-value of the wall = 0.3 The plastic foam reduces energy transfer by convection. Explain why. Filling the air gap with plastic foam reduces the U-value of the wall. What is meant by the term U-value? Page 14 of 32

15 (c) A homeowner has part of the outside wall of her house removed and replaced with doubleglazed glass doors. U-value of the wall = 0.3 U-value of glass doors = 1.8 Explain the effect of replacing part of the outside wall with glass doors on the rate of energy transfer from the house (Total 11 marks) Q10. The picture shows a washing machine. When the door is closed and the machine switched on, an electric motor rotates the drum and washing. (a) Complete the following sentences. An electric motor is designed to transform electrical energy into... energy. Some of the electrical energy supplied to the motor is wasted as... energy and... energy. (b) What happens to the energy wasted by the electric motor? Page 15 of 32

16 (c) The graph shows that washing clothes at a lower temperature uses less energy than washing them at a higher temperature. Using less energy will save money. Temperature setting in C Electricity costs 15p per kilowatt-hour (kwh). The temperature setting is turned down from 40 C to 30 C. Use the graph and equation in the box to calculate the money saved each wash cycle. total cost = number of kilowatt-hours x cost per kilowatt-hour Show clearly how you work out your answer. Money saved =... Reducing the amount of energy used by washing machines could reduce the amount of carbon dioxide emitted into the atmosphere. Explain why. (Total 7 marks) Page 16 of 32

17 Q11. (a) In the UK, over 70% of the electricity is generated in power stations that burn fossil fuels. Explain one effect that burning fossil fuels has on the environment. Give one way the effect on the environment described in part (a) could be reduced. Assume the amount of fossil fuels burnt stays the same. (b) Electricity can also be generated in a pumped storage hydroelectric power station. An advantage of pumped storage hydroelectric power stations is the short start-up time they have. What is the importance of the short start-up time? Give one other advantage of a pumped storage hydroelectric power station. (c) Read the extract below from a newspaper article. In the UK, the proportion of electricity generated using wind turbines is due to increase a lot. Some opponents of wind turbines think this increase will cause big fluctuations in the electricity supply. Suggest one reason why this may be true. Page 17 of 32

18 Between 2002 and 2008 the amount of electricity used for lighting in homes in the UK decreased. Suggest one reason why. (Total 7 marks) Q12. (a) The diagram shows the electromagnetic spectrum. The pictures show four devices that use electromagnetic waves. Each device uses a different type of electromagnetic wave. Draw a line from each device to the type of electromagnetic wave that it uses. One has been done for you. (3) (b) A headline from a recent newspaper article is shown below. What serious health problem may be caused by using a sunbed too much? Page 18 of 32

19 The pie chart compares the number of deaths in Britain each year which may have been caused by using sunbeds too much, with those which may have been caused by too much exposure to the Sun. It is difficult for a doctor to be certain that a person has died because of using a sunbed too much. Suggest why. (iii) A spokesperson for a leading cancer charity said: We want people, especially young people, to know the possible dangers of using a sunbed. Why is it important that you know the possible dangers of using a sunbed? (Total 6 marks) Page 19 of 32

20 Q13. The picture shows a temporary road traffic information board. The batteries power the LEDs used in the information board. The solar cells keep the batteries charged. (a) Use words from the box to complete each of the following sentences. chemical electrical light sound The solar cells transfer light energy to... energy. The batteries transfer... energy to electrical energy. The LEDs transfer electrical energy to... energy. (3) (b) When the total energy input to the solar cells is 200 joules, the useful energy output from the solar cells to the batteries is 50 joules. Calculate the efficiency of the solar cells. Use the correct equation from the Physics Equations Sheet Efficiency =... Page 20 of 32

21 (c) Which one of the following statements gives the reason for using solar cells to charge the batteries? Tick ( ) one box. Solar cells will charge the batteries day and night. The information board can be used anywhere it is needed. A small number of solar cells produce a lot of electricity. (Total 6 marks) Q14. Galaxies emit all types of electromagnetic wave. (a) Which type of electromagnetic wave has the shortest wavelength? State one difference between an ultraviolet wave and a visible light wave. (b) Electromagnetic waves travel through space at a speed of 3.0 x 10 8 m/s. The radio waves emitted from a distant galaxy have a wavelength of 25 metres. Calculate the frequency of the radio waves emitted from the galaxy and give the unit. Use the correct equation from the Physics Equations Sheet Frequency =... (3) Page 21 of 32

22 (c) Scientists use a radio telescope to measure the wavelength of the radio waves emitted from the galaxy in part (b) as the waves reach the Earth. The scientists measure the wavelength as 25.2 metres. The effect causing this observed increase in wavelength is called red-shift. The waves emitted from most galaxies show red-shift. What does red-shift tell scientists about the direction most galaxies are moving? The size of the red-shift is not the same for all galaxies. What information can scientists find out about a galaxy when they measure the size of the red-shift the galaxy produces? (iii) What does the observation of red-shift suggest is happening to the Universe? (Total 9 marks) Q15. The figure below shows a car with an electric motor. The car is moving along a flat road. (a) Use the correct answers from the box to complete each sentence. light electrical kinetic potential sound The car s motor transfers... energy into useful... energy as the car moves. Some energy is wasted as... energy. (3) Page 22 of 32

23 What happens to the wasted energy? (b) The electric motor has an input energy of joules each second. The motor transfers joules of useful energy each second. Calculate the efficiency of the electric motor. Use the correct equation from the Physics Equations Sheet Efficiency =... (Total 6 marks) Q16. (a) Diagram 1 shows two waves. Diagram 1 Name one wave quantity that is the same for the two waves. Name one wave quantity that is different for the two waves. Page 23 of 32

24 (iii) The waves in Diagram 1 are transverse. Which one of the following types of wave is not a transverse wave? Draw a ring around the correct answer. gamma rays sound visible light (b) Diagram 2 shows water waves in a ripple tank moving towards and passing through a gap in a barrier. Diagram 2 The water waves spread out after passing through the gap in the barrier. What name is given to the process causing the waves to spread out? Every second, 8 waves pass through the gap in the barrier. The waves have a wavelength of metres. Calculate the speed of the water waves and give the unit. Use the correct equation from the Physics Equations Sheet. Speed =... (3) (Total 7 marks) Page 24 of 32

25 Q17. Electricity can be generated using various energy sources. (a) Give one advantage and one disadvantage of using nuclear power stations rather than gas-fired power stations to generate electricity. Advantage Disadvantage (b) A single wind turbine has a maximum power output of W. The wind turbine operated continuously at maximum power for 6 hours. Calculate the energy output in kilowatt-hours of the wind turbine. Use the correct equation from the Physics Equations Sheet. Energy output =... kwh Why, on average, do wind turbines operate at maximum power output for only 30% of the time? (c) An on-shore wind farm is made up of many individual wind turbines. They are connected to the National Grid using underground power cables. Give one advantage of using underground power cables rather than overhead power cables (Total 6 marks) Page 25 of 32

26 Q18. Waves may be longitudinal or transverse. (a) Describe the differences between longitudinal waves and transverse waves (3) (b) Radio waves are electromagnetic waves. Describe how radio waves are different from sound waves (4) (Total 7 marks) Page 26 of 32

27 Q19. An electric immersion heater is used to heat the water in a domestic hot water tank. When the immersion heater is switched on the water at the bottom of the tank gets hot. (a) Energy is transferred by the process of convection from the hot water at the bottom of the tank to the cooler water at the top. Explain how (4) (b) Complete the following sentence. The main way the energy is transferred through the copper wall of the water tank is by the process of.... Page 27 of 32

28 (c) The immersion heater has a thermostat to control the water temperature. When the temperature of the water inside the tank reaches 58 C the thermostat switches the heater off. The thermostat switches the heater back on when the temperature of the water falls to 50 C. Graph A shows how the temperature of the water inside a hot water tank changes with time. The tank is not insulated. Time in hours The temperature of the water falls at the fastest rate just after the heater switches off. Explain why. To heat the water in the tank from 50 C to 58 C the immersion heater transfers 4032 kj of energy to the water. Calculate the mass of water in the tank. Specific heat capacity of water = 4200 J/kg C Use the correct equation from the Physics Equations Sheet. Mass =... kg (3) Page 28 of 32

29 (iii) An insulating jacket is fitted to the hot water tank. Graph B shows how the temperature of the water inside the insulated hot water tank changes with time. An insulating jacket only costs 12. Time in hours By comparing Graph A with Graph B, explain why fitting an insulating jacket to a hot water tank saves money. (3) (Total 13 marks) Page 29 of 32

30 Q20. (a) In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. 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 (6) Page 30 of 32

31 (b) Arctic foxes live in a very cold environment. Purestock/Thinkstock Arctic foxes have small ears. How does the size of the ears help to keep the fox warm in a cold environment? (Total 8 marks) Page 31 of 32

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