Name __________________________Classes 9 A, B, C, D
Must Show all Work
Mock Test #5: Chapters 4.05 – 4.08, All of Chapter 5
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Physics 17/02/15
Matching: USE CAPITAL LETTERS (A, B, C, ...) for answering Numbers 1 through 8
Match the following terms with the correct definition. There is at least one extra term that will not
match any of the definitions. USE CAPITAL LETTERS (A, B, ..)
A.
B.
C.
D.
E.
F.
G.
H.
I.
J.
K.
L.
M.
N.
O.
P.
Q.
H 1.
non-renewable energy resource
absorber
ice point
heat capacity
convection
Sankey Diagram
linear scale
conduction
renewable energy resource
Specific heat capacity
Charles’s Law
emitter
Kinetic Theory
thermal expansion
evaporation
absolute zero
Latent heat
is the process that details how heat is transferred from the hot part to the cold part of an object
M 2. describes how solids, liquids, and gases behave
A 3. natural gas, for example
D 4. This is equal to the quantity of mc
P 5. Is the name for the temperature of zero Kelvins (or 0 K)
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Name __________________________Classes 9 A, B, C, D
Must Show all Work
V1
Physics 17/02/15
(Past Paper IGCSE MC questions)
C 6. A mercury thermometer with no scale is taped to a ruler as shown. When the thermometer is placed in
steam, the mercury level rises to 22.0 cm. When the thermometer is placed in pure melting ice, the
mercury level falls to 2.0 cm.
Which temperature is shown by the mercury level in the diagram?:
a. 6 C
b. 8 C
c. 30 C
d. 40 C
e. None of these choices are correct
We can see this as follows: the steam point is at 100 C. The ice point is at 0 C. This is a rise in
temperature of 100 C. Next we need to focus on the ruler. The steam point is at 22 cm. The ice point is at
2 cm. This is a difference of 22 cm – 2 cm = 20 cm. Now we can relate the un-scaled thermometer to the
scaled ruler. This is critical in solving these types of problems. We have a 100 C increase equaling a 20 cm
height difference. So if we divide 100 C by 20 cm we have a ratio of 5 C per 1 cm increase on the ruler.
But we want to know what temperature the thermometer reads when the ruler reads 8 cm.
5℃
Since 8 cm – 2 cm = 6 cm, this means that 6 cm ∙ 1 cm = 30 ℃.
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Name __________________________Classes 9 A, B, C, D
Must Show all Work
V1
Physics 17/02/15
(Medium Difficulty Questions)
7. Name three non-renewable energy resources. One of your answers should not burn to release energy.
Describe them in detail using the Kinetic Theory.
For example:
1. Coal. Coal is a black solid. Its molecules vibrate in fixed position. As a solid, it has a fixed shape and
volume. It is very incompressible.
2. Oil. Oil is a black liquid. Its molecules vibrate is relatively fixed positions but are able to move about
a bit. The interactions and forces between neighboring particles have become less thus allowing
the liquid to have no fixed shape even though the overall volume is fixed. Oil can take the shape of
any container in which it is being held.
3. Nuclear fuel is the energy that does not burn. Instead, it is energy released by the splitting of
atoms. Most nuclear material, like Uranium, is a solid. As a solid, it has a fixed shape and volume. It
is very incompressible.
(Difficult Problem)
8. The figure below shows a device called a thermostat, which is being used to control the temperature of the
air in a room. X and Y are two strips of two different metals, joined together along their length. Together
they are called a bimetallic strip. X expands more than Y for the same temperature rise.
The temperature rises and the bimetallic strip bends.
a. Which way does the strip bend?
To the right.
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Name __________________________Classes 9 A, B, C, D
Must Show all Work
V1
Physics 17/02/15
b. What happens to the contacts?
The contacts separate from each other.
c. What happens to the current in the circuit?
Since the circuit has been broken (the contacts no longer touch each other), the electrical signals stop
and the power is cut off, and the heater stops working.
d. What adjustments could be made to this thermostat, in order to increase the temperature at which
the thermostat operates?
Ibrahim from 9A: “We can change the metals X and Y to other metals”. Correct. By doing this we can
change metal X to invar, for example. We would want the new metal X to have a lower expansion rate,
so that it takes much more heat (increase in temperature) to cause the strip to bend.
Another adjustment: Turn the knob controlling the thermostat to the right, forcing the bimetal strip to
be bent to the right further than before, so that when the temperature starts to increase, a higher
temperature would be needed to begin bending the bimetal strip so that the contacts separate again.
The next figure shows how the temperature of the water in the tank would rise if it were heated continuously,
starting with the water at a temperature of 0 C
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Name __________________________Classes 9 A, B, C, D
Must Show all Work
V1
Physics 17/02/15
The thermostat controlling the temperature of the water switches off the heater current when the temperature
rises above 50 C.
e. Use the above diagram to determine how long, in minutes, the water is heated before the thermostat
operates.
As you can see form this diagram, once 50 C is reached, it takes about 29 minutes. Draw a horizontal
(straight line across from the y-axis) from 50 C to where the black curved line meets. Then drop a vertical
line straight down to the x-axis. The nearest time is 29 minutes.
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