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Diego	

	Name:	
________________________	

Class:	
________________________	

Date:	
________________________	

 	
Time:	102 minutes	
Marks:	101 marks	
Comments:		

Q1.
The diagram below shows a girl skateboarding on a semi-circular ramp.
 
The girl has a mass of 50 kg
(a)  Calculate the gravitational potential energy (g.p.e.) of the girl at the top of the ramp.
Use the equation:
g.p.e. = mass × gravitational field strength × height
gravitational field strength = 9.8 N/kg
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g.p.e. = ________________________ J
(2)
(b)  The girl has a speed of 7 m/s at the bottom of the ramp.
Calculate the kinetic energy of the girl at the bottom of the ramp.
Use the equation:
kinetic energy = 0.5 × mass × (speed)2
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Kinetic energy = ________________________ J
(2)
(c)  Not all of the g.p.e. has been transferred to kinetic energy.
Which two statements explain why?
Tick two boxes.
 
Some energy is wasted.		
The mass of the girl is too low.		
The ramp is not high enough.		
The g.p.e. of the girl is not zero.		
The speed of the girl is too great.		
(2)
(d)  Explain how lubricating the wheels of the skateboard can increase the speed of the girl.
Use ideas about energy in your explanation.
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(3)
(Total 9 marks)
Q2.
A heater uses energy from a laptop computer to keep a drink hot.
The image shows a metal mug on the heater.
 
(a)     The laptop computer is operating on battery power.
How would connecting the heater affect the amount of time the laptop computer would operate for, before needing to be recharged?
Tick (✔) one box.
 
 	Tick (✔)	
it would decrease the time	 	
it would not affect the time	 	
it would increase the time	 	
(1)
(b)     The power output from the heater is 12 W.
Calculate the energy transferred to the metal mug in 60 seconds.
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Energy = ________ joules
(2)
(c)     The table lists changes that may affect the energy transfer per second from the heater to the liquid.
Tick (✔) one box to show the effect of each change.
 
Change	Energy transfer per second to the liquid	
	increases	decreases	does not change	
use a mug with a smaller base	 	 	 	
use a lower power heater	 	 	 	
use a plastic mug instead of a metal mug	 	 	 	
(3)
(Total 6 marks)
Q3.
A student did an experiment to calculate her power.
The diagram below shows how she obtained the measurements needed.
The student first weighed herself and then ran up a flight of stairs. A second student timed how long it took her to go from the bottom to the top of the stairs. The height of the stairs was also measured.
 
(a)     Complete the following sentence.
To run up the stairs the student must do work against
the force of ___________ .
(1)
(b)     The student did 2240 J of work going from the bottom of the stairs to the top of the stairs.
The student took 2.8 seconds to run up the stairs.
(i)      Calculate the power the student developed when running up the stairs.
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Power = ___________ W
(2)
(ii)     How much gravitational potential energy did the student gain in going from the bottom to the top of the stairs?
Tick (✔) one box.
 
much more than 2240 J		
2240 J		
much less than 2240 J		
(1)
(c)     Another four students did the same experiment.
The measurements taken and the calculated values for power are given in the table.
 
Student	Weight in newtons	Time taken in seconds	Power in watts	
A	285	3.8	240	
B	360	2.4	480	
C	600	3.4	560	
D	725	4.0	580	
(i)      To make a fair comparison of their powers the students kept one variable in the experiment constant.
What variable did the students keep constant?
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(1)
(ii)     From the data in the table a student wrote the following conclusion.
'The greater the weight of the student the greater the power developed.'
Suggest why this conclusion may not be true for a larger group of students.
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(1)
(Total 6 marks)
Q4.
All European Union countries are expected to generate 20% of their electricity using renewable energy sources by 2020.
The estimated cost of generating electricity in the year 2020 using different energy sources is shown in Table 1.
Table 1
 
Energy source	Estimated cost (in the year 2020) in pence per kWh	
Nuclear	7.8	
Solar	25.3	
Tidal	18.8	
Wind	10.0	
France generated 542 billion kWh of electricity using nuclear power stations in 2011.
France used 478 billion kWh of electricity and sold the rest of the electricity to other countries in 2011.
(a)     France may continue generating large amounts of electricity using nuclear power stations instead of using renewable energy resources.
Suggest two reasons why.
1. _________________________________________________________________
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2. _________________________________________________________________
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(2)
(b)     Give two disadvantages of generating electricity using nuclear power stations.
1. _________________________________________________________________
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2. _________________________________________________________________
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(2)
(c)     A panel of solar cells has an efficiency of 0.15.
The total power input to the panel of solar cells is 3.2 kW.
Calculate the useful power output of this panel of solar cells in kW.
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Useful power output = _______________ kW
(2)
(d)     Table 2 shows the manufacturing cost and efficiency of different types of panels of solar cells.
Table 2
 
Type of Solar Panel	Cost to manufacture a 1 m2 solar panel in £	Efficiency in %	
A	40.00	20	
B	22.50	15	
C	5.00	10	
Some scientists think that having a low manufacturing cost is more important than improving the efficiency of solar cells.
Use information from Table 2 to suggest why.
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(2)
(Total 8 marks)
Q5.
A new design for a kettle is made from two layers of plastic separated by a vacuum.
After the water in the kettle has boiled, the water stays hot for at least 2 hours.
The new kettle is shown below.
 
(a)     The energy transferred from the water in the kettle to the surroundings in 2 hours is 
46 200 J.
The mass of water in the kettle is 0.50 kg.
The specific heat capacity of water is 4200 J/kg °C.
The initial temperature of the water is 100 °C.
Calculate the temperature of the water in the kettle after 2 hours.
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Temperature after 2 hours = ___________ °C
(3)
(b)     Calculate the average power output from the water in the kettle to the surroundings in 2 hours.
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Average power output = ______________ W
(2)
(Total 5 marks)
Q6.
Figure 1 shows the main energy transfers from a house.
Figure 1
 
(a)  Which two changes to the house would reduce the rate of energy transfer?
Tick two boxes.
 
Add thermal insulation to the roof		
Increase the temperature of the house		
Decrease the thickness of the walls		
Replace the single-glazed windows with double-glazed windows		
Use materials with a higher thermal conductivity		
(2)
The temperature inside the house is controlled using a thermostat.
The thermostat switches the heating on when the temperature drops below a chosen value.
The thermostat switches the heating off when the temperature rises above the chosen value.
Figure 2 shows how the temperature of the house changes over a 150 minute period.
Figure 2
 
(b)  For how many minutes was the heating switched on?
Number of minutes = ____________________
(1)
(c)  The householder installs cavity wall insulation.
What would happen to the time taken for the temperature to fall between points A and B?
Tick one box.
 
The time taken decreases		
The time taken increases		
The time taken stays the same		
(1)
(d)  The householder has solar panels installed on the roof to heat water.
The householder can also heat water with an immersion heater which uses mains electricity.
Explain one advantage and one disadvantage of using a solar panel to heat water for the house, compared to the immersion heater.
Advantage __________________________________________________________
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Disadvantage _______________________________________________________
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(4)
(Total 8 marks)
Q7.
The electric kettle shown below is used to boil water.
 
©leeser87/iStock
(a)     After the water has boiled, the temperature of the water decreases by 22 °C.
The mass of water in the kettle is 0.50 kg.
The specific heat capacity of water is 4200 J/kg °C.
Calculate the energy transferred to the surroundings from the water.
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Energy = ____________ joules
(2)
(b)     Why is the total energy input to the kettle higher than the energy used to heat the water?
Tick (✔) one box.
 
 	Tick (✔)	
Energy is absorbed from the surroundings.	 	
Energy is used to heat the kettle.	 	
The kettle is more than 100% efficient.	 	
(1)
(Total 3 marks)
Q8.
Electricity in the UK is generated in many ways.
The figure below shows an undersea turbine.
The undersea turbine uses tidal energy to generate electricity.
 
© alex-mit/iStock/Thinkstock
(a)     What is the original source of energy for tidal power schemes?
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(1)
(b)     Explain two advantages of using undersea tidal turbines to generate electricity rather than burning fossil fuels.
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(4)
(c)     Some power stations burn wood instead of fossil fuels to generate electricity.
A coal-burning power station burns 6 million tonnes of coal per year.
Coal has an average energy value of 29.25 MJ per kg.
Wood chip from willow trees has an energy value of 13 MJ per kg.
A hectare of agricultural land can produce 9 tonnes of dry willow wood per year.
If this power station burned dry willow wood instead of coal, how much agricultural land would be needed to grow the willow?
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Amount of land needed = _____________ hectares
(3)
(d)     The table below shows the carbon dioxide emissions of four fuels used to generate electricity.
 
Fuel	Direct CO2 emissions
in kg per MWh	Lifecycle CO2 emissions
in kg per MWh	
Coal	   460	540	
Natural gas	   185	215	
Oil	   264	313	
Wood	2 100	  58	
Direct CO2 emissions are the amounts of carbon dioxide released when the fuel is burned.
Lifecycle CO2 emissions is the total amount of carbon dioxide released during all stages from fuel extraction to when the fuel has been used.
Use the data from the table above to explain why wood is considered to be a low carbon dioxide emitting fuel.
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(2)
(Total 10 marks)
Q9.
Different energy sources are used to generate electricity.
(a)     Use words from the box to match the correct energy source to each of the descriptions given in the table.
 
biofuel	coal	geothermal	nuclear	waves	
 
Description	Energy source	
Energy from the Earth’s core is used to heat water.	 	
Fission of uranium nuclei is used to heat water.	 	
Gases from rotting plant material are burned to heat water.	 	
(3)
(b)     Energy can be stored in a pumped storage power station.
The figure shows a pumped storage power station.
 
When electricity is needed, the water in the high level reservoir is allowed to flow to the low level reservoir. The flowing water generates electricity.
Use the correct answer from the box to complete each sentence.
 
electrical	gravitational potential	kinetic	nuclear	sound	
The water in the high level reservoir stores ____________ energy.
The flowing water has ____________ energy.
The water turns the turbine which is connected to the generator.
The generator produces some ____________, this is wasted energy.
(3)
(c)     The total power input to a pumped storage power station is 600 MW.
The useful power output is 540 MW.
(i)      Calculate the efficiency of this pumped storage power station.
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Efficiency = _______________
(2)
(ii)     Calculate how much power is wasted by the pumped storage power station.
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Power = ______________ MW
(1)
(iii)    How is the temperature of the surroundings affected by the energy wasted by the pumped storage power station?
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(1)
(Total 10 marks)
Q10.
Astronauts have been to the Moon.
(a)  Astronauts moved around the surface of the Moon in a lunar rover.
The photograph below shows a lunar rover.
 
The batteries on the lunar rover provided a potential difference of 36 V
The total charge stored in the batteries was 870 000 C
Calculate the maximum energy that could have been transferred from the batteries.
Use the equation:
energy transferred = charge flow × potential difference
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Maximum energy transferred = _________________________ J
(2)
(b)  Not all of the energy from the batteries was usefully transferred to the kinetic energy of the lunar rover.
Explain why.
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(2)
The astronauts collected rock samples from the Moon.
Scientists analysed the percentages of elements in Moon rock and Earth rock.
The table below shows the results.
 
Element	Percentage in Moon rock	Percentage in Earth rock	
Aluminium	8	8	
Iron	13	5	
Oxygen	42	47	
Silicon	X	28	
Other elements	10	12	
(c)  Calculate value X in the table above.
X = ____________ %
(1)
(d)  Give one similarity and one difference between Moon rock and Earth rock.
Use the table above.
Similarity ___________________________________________________________
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Difference __________________________________________________________
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(2)
(e)  Scientists used to think the Earth and Moon formed separately.
Scientists now believe that the Moon formed after a collision between the Earth and a small planet.
This new idea came from the study of Moon rocks.
Why do scientific theories sometimes change?
Tick one box.
 
Scientists agree that the existing theory is old-fashioned		
Scientists change their theories to make the theories more popular		
Scientists decide that the new theory is more exciting		
Scientists discover new evidence which the existing theory cannot explain		
(1)
(f)  Write down the equation which links gravitational field strength, gravitational potential energy, height and mass.
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(1)
(g)  When the astronauts left the Moon, they used a spacecraft with a mass of 2150 kg
Calculate the height reached by the spacecraft at the point where it had a gravitational potential energy of 86 000 000 J
The gravitational field strength of the Moon is 1.6 N/kg
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Height = _______________ m
(3)
(Total 12 marks)
Q11.
Figure 1 shows cavity wall insulation being installed in the wall of a house.
Figure 1
 
(a)  Explain how the wall reduces unwanted energy transfers.
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(3)
(b)  The cavity insulation was tested.
•   The heating inside the house was switched off.
•   The temperature inside the house was measured every 20 minutes for 2 hours.
The table below shows the results.
 
Time in minutes	Temperature in °C	
0	25.0	
20	20.8	
40	17.4	
60	14.5	
80	12.1	
100	10.0	
120	8.4	
Determine the temperature inside the house after 30 minutes.
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Temperature = _____________________ °C
(2)
(c)  Figure 2 shows the gas boiler used to heat the house.
Figure 2
 
Describe how different energy stores are changed by the boiler.
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(3)
(d)  To heat the house, the boiler transfers 15 MJ of energy in 10 minutes.
Calculate the power of the boiler.
Write any equation that you use.
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Power = _____________________ W
(4)
(Total 12 marks)
Q12.
A student investigated how the temperature of a metal block changed with time.
An electric heater was used to increase the temperature of the block.
The heater was placed in a hole drilled in the block as shown in Figure 1.
Figure 1
 
The student measured the temperature of the metal block every 60 seconds.
The table below shows the student’s results.
 
Time in s	Temperature in °C	
0	20.0	
60	24.5	
120	29.0	
180	31.0	
240	31.5	
(a)  Complete the graph of the data from the table above on the graph below.
•   Choose a suitable scale for the x-axis.
•   Label the x-axis.
•   Plot the student’s results.
•   Draw a line of best fit.
Figure 2
 
(4)
(b)  The rate of change of temperature of the block is given by the gradient of the graph.
Determine the gradient of the graph over the first 60 seconds.
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Gradient = _____________________
(2)
(c)  The metal block had a mass of 1.50 kg
The specific heat capacity of the metal was 900 J/kg °C
Calculate the change in thermal energy of the metal during 240 seconds.
Use the Physics Equations Sheet.
Give your answer in kilojoules.
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Change in thermal energy = __________________ kJ
(4)
(d)  Another student repeated the investigation.
Give two variables this student would need to control to be able to compare their results with the results in the table above.
1. _________________________________________________________________
2. _________________________________________________________________
(2)
(Total 12 marks)