Year 7 – Assessed Homework
As we approach the end of the topic, here are some revision questions that get progressively harder.
Try to do them without any help, but if you get stuck use other resources to help you.
Name:_________________________________________
1.
Class:______________________
Meera used the Internet to find out about energy resources. The drawing below shows what
Meera saw on her computer screen.
(a)
Coal is a fossil fuel.
Give the names of two other fossil fuels in the list on the screen.
……oil…......and………natural gas.....…………..….
2 marks
(b)
(i)
Wave energy is an example of a renewable energy resource.
From the list on the screen above choose two other renewable energy resources.
Any two from wind, solar, tidal, geothermal
2 marks
(ii)
Meera found out how wave energy can be used to generate electricity.
She saw the diagram below on the Internet.
Each box below shows a stage in generating electricity.
A
The air turns the turbine.
B
The turbine turns the
generator.
C
The waves move up the
chamber.
D
The generator produces
electricity.
E
The waves push the air
up the chamber.
On the lines below write the letters of the stages in the correct order.
Two have been done for you.
.....C.....
...E.....
......A......
...B.....
....D.....
2 marks
Maximum 6 marks
2.
The drawings below show what happens to the energy supplied to four appliances.
98% of the energy is
used to heat the water
kettle
2% of the energy is wasted
5
% of the energy
is given out as light
light bulb
95% of the energy is wasted
50% of the energy
is given out as sound
radio
50% of the energy is wasted
40% of the energy is
used to move the whisks
mixer
60
(a)
(i)
% of the energy is wasted
What percentage of energy of the light bulb is given out as light?
Write your answer on the line by the light bulb.
1 mark
(ii)
What percentage of energy is wasted by the mixer?
Write your answer in the box by the mixer.
1 mark
(iii)
Complete the sentence below.
Parts of the mixer become hot because some of the electrical
energy is changed into ...Heat or thermal..... energy which is
wasted.
1 mark
(b)
Energy is wasted as sound in many appliances.
Which appliance in the drawings produces sound which is not wasted?
.........Radio.............
1 mark
(c)
In which of the appliances is the highest percentage of energy wasted?
...........Light bulb...............
1 mark
Maximum 5 marks
3.
The diagram shows a cyclist at different positions as he cycles over a humpback bridge.
(a)
(i)
Where does the cyclist have the most kinetic energy?
Tick the correct box.
A
B
C
D
1 mark
(ii)
Where does the cyclist have the most potential energy?
Tick the correct box.
A
B
C
D
1 mark
(iii)
Where does the cyclist have the least potential energy?
Tick the correct box.
A
B
C
D
1 mark
(b) The cyclist used some energy to cycle over the bridge. Where was this energy transferred to
by the time the cyclist reached position D?
................To the surroundings.....................
1 mark
Maximum 4 marks
4.
The tides can be used to generate electricity. A dam is built across a river estuary, as
shown below.
dam
water level
turbine spins
to generate
electricity
water level
water flow
sea bed
(a)
sea bed
The water is higher on one side of the dam than on the other. As the water begins to flow
through the dam it turns a turbine. The turbine generates electricity.
Describe the useful energy changes which take place in this process.
Gravitational potential behind the dam  kinetic through the turbine  electrical
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
2 marks
(b)
Explain why tides are classified as a renewable energy source.
.......Because it can quickly replenish itself and be used again, it never runs out
.........................................................................................................................
1 mark
(c)
Give one way, other than from the tides, of generating electricity by using the sea.
......wave.........
1 mark
(d)
Apart from cost, give one advantage and one disadvantage of an oil-fired power station
compared with a tidal power station.
advantage ......produces electricity all the time, produces large amounts of electricity,
.........................................................................................................................
disadvantage .produces carbon dioxide which leads to the greenhouse effect, uses a nonrenewable energy resource
.........................................................................................................................
2 marks
Maximum 6 marks
5.
Fossil fuels are used to generate electricity, but over half of the world’s population uses
biomass as a fuel.
(a)
What is ‘biomass’, which is used as a fuel?
Wood is classed as biomass – it means the mass of living material
1 mark
(b)
Biomass and fossil fuels are both energy resources. What is the original source
of this energy?
The Sun..................................................................................
..........................................................................................................................
1 mark
(c)
Give the names of three fossil fuels which are often burned to generate electricity.
1. ....Coal..................................
2. .....Oil.........................................
3. .....Gas.......................................
1 mark
(d)
Fossil fuels are often described as non-renewable energy resources.
Explain why they are called ‘non-renewable’.
....Once used they cannot be re-used as it takes millions of years to make a fossil fuel.....
..........................................................................................................................
1 mark
(e)
There are advantages and disadvantages of burning different fuels.
(i)
Give one advantage of using biomass rather than fossil fuel as an energy resource.
......Can grow more trees or use the waste from animals.....
.................................................................................................................
1 mark
(ii)
Give one advantage of using fossil fuel rather than biomass as an energy resource.
Large amounts of electricity are produced as 1 tonne of coal is the same as burning 2
tonnes of wood.
.................................................................................................................
1 mark
(iii)
Give one disadvantage of using both fossil fuel and biomass.
They both produce CO2
1 mark
Maximum 7 marks
7.
A headline from a newspaper is shown below.
British Power
Stations cause
Acid Rain in
Scandanavia
Some countries claim that acid rain caused by power stations in Britain damages their
forests.
Others argue that coal-burning power stations produce cheap electricity and that plants
can stand some level of acid rain.
Imagine you are planning a laboratory investigation of the claim:
‘plants can stand some level of acid rain’.
Assume you have access to whatever laboratory equipment you need, including:

seeds

acid

seed trays

soil
Plan a laboratory investigation to test the claim that ‘plants can stand some level of acid
rain’.
(a)
Name a factor you would need to vary in your investigation.
(This is the independent variable.)
.....The amount of acid.............................
1 mark
(b)
(i)
What factor would you examine to see the effect?
(This is the dependent variable.)
....Plant growth.....
.............................................................................................................
1 mark
(ii)
How could you measure this dependent variable?
.....Length of plant shoots........................................
1 mark
(c)
Suggest one factor you would control to ensure that your investigation is fair.
............light, water, nutrients, soil, type of seed........................
1 mark
Maximum 4 marks
8.
The drawing shows what happens to most of the energy in the food that a hen eats in one day.
(a)
In the cells of the hen's body, energy is released from food by respiration
Complete the word equation for this process.
Glucose + …oxygen…  …carbon dioxide… + …water……..
1 mark
(b)
(i)
Calculate the total energy which remains in the body of the hen
.................................................................................................................
.......................................................................................200... kJ
1 mark
(ii)
What is this energy used for?
......MRS GREN.............................................................
.................................................................................................................
1 mark
(c)
Suggest how farmers might reduce the amount of energy which hens lose each day by
thermal transfer.
.......Keep them indoors or in a hen house............
..........................................................................................................................
1 mark
(d)
Farmers can reduce the amount of energy which is transferred by movement and thermal
transfer from hens. Suggest two reasons why this is cost-effective.
1. .... more energy used for producing eggs
.......................................................................................................................
2. ...More energy used for producing meat [chicken]...
..........................................................................................................................2 marks
Maximum 6 marks