CHAPTER 6
ENERGY
Question
Topic
Need to revise
1 to 9
MCQ
/ 10
10
Energy efficiency
/5
11
GPE
/8
12
Energy disipated
/5
13
Energy transfer
/4
Name ______________ Class________
You have 30 minutes to complete this test.
Do not leave any questions unanswered.
Marks: ___ / 32
Level:
___
My targets are:
1. Energy is...
A. Power
B. When the surfaces of two objects rub against each other.
C. The ability to do work.
D. None of the above
2. Sound energy is...
A. The energy of a compound that changes as its atoms are rearranged to form new
compounds.
B. The total energy of the particles that make up an object.
C. The energy caused by an object's vibrations.
D. The energy of motion.
3. What device converts chemical energy to Kinetic energy?
A. Human
B. Car
C. jet ski
D. All of the above.
4. Which of the following is a conversion from chemical energy to thermal energy?
A. Coal is burned to boil water.
B. Food is digested and used to regulate body temperature.
C. Charcoal is burned in a barbeque pit.
D. All of the above.
5. An object that has kinetic energy must be...
A. Lifted above earth's surface.
B. In motion.
C. At rest.
D. None of the above.
6. Jacquie has a mobile phone. Energy is stored in the battery of the phone. The drawing shows
the battery being charged.
i.)
Which energy transfer takes place in the battery as it is being charged?
A. chemical to sound
B. sound to thermal
C. electrical to chemical
D. thermal to electrical
ii.)
When the battery is fully charged, Jacquie unplugs the phone. Which energy transfers
take place when the mobile phone rings? Tick the correct box.
A. chemical to electrical to sound
B. electrical to chemical to sound
C. kinetic to electrical to sound
D. thermal to electrical to sound
7. Energy is measured in …
A. Joules
B. Kilograms
C. Metres
D. Newtons
8. An airplane is slowing down and flying lower as it prepares to land at an airport. Which
statement best describes the energy of the airplane?
A. The kinetic energy decreases and the potential energy decreases.
B. The kinetic energy decreases and the potential energy increases.
C. The kinetic energy increases and the potential energy decreases.
D. The kinetic energy increases and the potential energy increases.
9. The picture shows a coloured printer
When this machine is working, it converts electrical energy into____________.
A - Sound Energy
B - Heat Energy
C - Kinetic Energy
Which option is correct:
A. A and B only
B. B and C only
C. A and C only
D. A, B, and C
10. The drawings below show what happens to the energy supplied to four appliances.
(a)
i.
(What percentage of energy of the light bulb is given out as light?
.............................................................................................................
1
mark
ii.
(What percentage of energy is wasted by the mixer?
.............................................................................................................
1
mark
iii.
Parts of the mixer become hot because some of the electrical energy is changed into
.......................................... 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?
...............................................................................................................................................
1 mark
(c) In which of the appliances is the highest percentage of energy wasted? 1 mark
...............................................................................................................................................
1 mark
Maximum 5 marks
11. . The photograph shows some pupils in a log car on a theme-park ride. The drawing below
shows the ride. The letters A, B, C, D, E and F show different points along the track.
The car starts from A and travels to F, where it stops by hitting a bumper. At E the car enters a trench
filled with water.
(a) (i) At which two points does the car have no kinetic energy?
.............................................................................................................
1 mark
(ii) At which point does the car have the most gravitational potential energy?
.............................................................................................................
1 mark
(iii) At which point does the car have some kinetic energy and the least gravitational potential
energy?
.............................................................................................................
1 mark
(b) (i) The cars are not powered by a motor. What force causes the cars to move along the track
from B to C?
.............................................................................................................
1 mark
(ii) When a car splashes through the water at E, it slows down. What force acts on the car
to slow it down?
.............................................................................................................
1 mark
(c) Complete the sentence below by choosing from the following words.
When the car hits the bumper at F, its ................................... energy is transferred into
.............................. energy and.............................. energy.
3 mark
maximum 8 marks
12. a.)The following diagrams represent the energy transfers that take place in a number of
devices used in the home.
Which diagram best shows the energy changes taking place in:
i)
an electric drill;
.............................................................................................................
ii)
an electric hot plate being used to boil a 1 litre pan of water;
............................................................................................................
iii)
1 mark
1 mark
an electric kettle being used to boil 1 litre of water?
.............................................................................................................
1 mark
b.) Omar puts a hot steel ball into a beaker of cold water. He waits until the temperatures of the
ball and the water are the same. From his results, he calculates that:
the thermal energy stored in the steel ball has fallen by 3770 J
the thermal energy stored in the water has risen by 2940 J
The energy stored in the water rose by less than 3770 J
What has happened to the other 830 J?
.....................................................................................................................................
.....................................................................................................................................
1 mark
maximum 4 marks
13. A flywheel is a heavy rotating wheel which is used to store energy.
(a) Energy must be transferred to a flywheel to make it rotate. How is the energy in the
rotating flywheel classified?
A. as chemical energy
B. as kinetic energy
C. as potential energy
D. as thermal energy
1 mark
(b) A flywheel is rotating at a high speed. No energy is being supplied to it. The flywheel is
used to turn a dynamo, and the energy from the dynamo is used to light a bulb.
(i)
The bulb is left connected until the flywheel stops rotating. Not all the energy
stored in the flywheel is transferred to the bulb. Some of it is lost.
Give two places from which it is lost, and explain how it is lost.
.....................................................................................................................................
.....................................................................................................................................
..................................................................................................................................... 2 marks
(ii)
The experiment is repeated using a different bulb which gives out more
energy each second. Compared to the first light bulb, describe how the
second light bulb will affect the motion of the flywheel, and explain your
answer.
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
.....................................................................................................................................
2 marks
Maximum 5 marks