1.
What is the mass of carbon-12 that contains the same number of atoms as 14 g of silicon-28?
A.
6g
B.
12 g
C.
14 g
D.
24 g
(Total 1 mark)
2.
This question is about mechanics and thermal physics.
The graph shows the variation with time t of the speed v of a ball of mass 0.50 kg, that has been
released from rest above the Earth’s surface.
The force of air resistance is not negligible. Assume that the acceleration of free fall is
g = 9.81 m s–2.
(a)
State, without any calculations, how the graph could be used to determine the distance
fallen.
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(1)
IB Questionbank Physics
1
(b)
(i)
In the space below, draw and label arrows to represent the forces on the ball at
2.0 s.
(1)
(ii)
Use the graph opposite to show that the acceleration of the ball at 2.0 s is
approximately 4 m s–2.
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(2)
(iii)
Calculate the magnitude of the force of air resistance on the ball at 2.0 s.
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(2)
IB Questionbank Physics
2
(iv)
State and explain whether the air resistance on the ball at t = 5.0 s is smaller than,
equal to or greater than the air resistance at t = 2.0 s.
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(2)
(c)
After 10 s the ball has fallen 190 m.
(i)
Show that the sum of the potential and kinetic energies of the ball has decreased by
780 J.
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(3)
(ii)
The specific heat capacity of the ball is 480 J kg–1 K–1. Estimate the increase in the
temperature of the ball.
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(2)
IB Questionbank Physics
3
(iii)
State an assumption made in the estimate in (c)(ii).
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(1)
(Total 14 marks)
3.
Oil with volume V has specific heat capacity c at temperature T. The density of oil is ρ.
Which of the following is the thermal capacity of the oil?
A.
B.
ρcV
cV

C.
ρcVT
D.
cV
T
(Total 1 mark)
4.
The volume of an ideal gas in a container is increased at constant temperature. Which of the
following statements is/are correct about the molecules of the gas?
I.
Their speed remains constant.
II.
The frequency of collisions of molecules with unit area of the container wall
decreases.
III.
The force between them decreases.
A.
I only
B.
I and II only
C.
I and III only
D.
II and III only
(Total 1 mark)
IB Questionbank Physics
4
5.
This question is about internal energy and thermal energy (heat).
(a)
Distinguish between internal energy and thermal energy.
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(3)
(b)
Describe, with reference to the energy of the molecules, the difference in internal energy
of a piece of iron and the internal energy of an ideal gas.
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......................................................................................................................................
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(2)
(c)
A piece of iron is placed in a kiln until it reaches the temperature θ of the kiln. The iron is
then quickly transferred to water held in a thermally insulated container. The water is
stirred until it reaches a steady temperature. The following data are available.
Thermal capacity of the piece of iron
Thermal capacity of the water
Initial temperature of the water
Final temperature of the water
= 60 J K–1
= 2.0 × 103 J K–1
= 16 °C
= 45 °C
The thermal capacity of the container and insulation is negligible.
(i)
State an expression, in terms of θ and the above data, for the energy transfer of the
iron in cooling from the temperature of the kiln to the final temperature of the
water.
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(1)
IB Questionbank Physics
5
(ii)
Calculate the increase in internal energy of the water as the iron cools in the water.
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(1)
(iii)
Use your answers to (c)(i) and (c)(ii) to determine θ.
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(2)
(Total 9 marks)
6.
This question is about solar heating panels.
(a)
State the energy change that takes place in a solar panel.
......................................................................................................................................
......................................................................................................................................
(1)
IB Questionbank Physics
6
(b)
A village consists of 120 houses. It is proposed that solar panels be used to provide hot
water to the houses.
The following data are available.
average power needed per house to heat water
= 3.0 kW
average surface solar intensity
= 650 W m–2
efficiency of energy conversion of a solar panel = 18 %
Calculate the minimum surface area of the solar panels required to provide the total
power for water heating.
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......................................................................................................................................
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......................................................................................................................................
(3)
(c)
Suggest two disadvantages of using solar power to provide energy for heating water.
1: ..................................................................................................................................
......................................................................................................................................
2: ..................................................................................................................................
......................................................................................................................................
(2)
(Total 6 marks)
7.
This question is about heating a liquid.
(a)
Suggest why, in terms of the molecular model, the energy associated with melting is less
than that associated with boiling.
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(2)
IB Questionbank Physics
7
(b)
Milk in a cup is heated to boiling point by passing steam through it. Whilst cooling
subsequently, some milk evaporates.
(i)
Distinguish between evaporation and boiling.
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(2)
(ii)
The cup contains 0.30 kg of milk at an initial temperature of 18 °C. Estimate the
minimum mass of steam at 100 °C that is required to heat the milk to 80 °C.
Specific latent heat of vaporization of water
Specific heat capacity of water
Specific heat capacity of milk
= 2.3 × 106 J kg–1
= 4200 J kg–1 K–1
= 3800 J kg–1 K–1
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(4)
IB Questionbank Physics
8
(iii)
State two reasons, other than evaporation, why the answer to (b)(ii) is likely to be
different from the actual mass of condensed steam.
1: .......................................................................................................................
...........................................................................................................................
2: .......................................................................................................................
...........................................................................................................................
(2)
(Total 10 marks)
8.
This question is about change of phase of a liquid and latent heat of vaporization.
(a)
State the difference between evaporation and boiling with reference to
(i)
temperature.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
surface area of a liquid.
...........................................................................................................................
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(1)
IB Questionbank Physics
9
(b)
A liquid in a calorimeter is heated at its boiling point for a measured period of time.
The following data are available.
Power rating of heater
Time for which liquid is heated at boiling point
Mass of liquid boiled away
= 15 W
= 4.5 × 102 s
= 1.8 × 10–2 kg
Use the data to determine the specific latent heat of vaporization of the liquid.
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(3)
(c)
State and explain one reason why the calculation in (b) will give a value of the specific
latent heat of vaporization of the liquid that is greater than the true value.
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(2)
(Total 7 marks)
9.
In which of the following places will the albedo be greatest?
A.
A forest
B.
A grassland
C.
An ocean
D.
A polar ice cap
(Total 1 mark)
IB Questionbank Physics
10
10.
A spherical black body has absolute temperature T1. The surroundings are kept at a lower
absolute temperature T2. What is the net power per unit area lost by the body?
A.
σT14
B.
σT24
C.
σ(T14 – T24)
D.
σ(T14 + T24)
(Total 1 mark)
11.
What is the unit of surface heat capacity?
A.
J kg–1 K–1
B.
J K–1
C.
J m–2 K–1
D.
J m–3 K–1
(Total 1 mark)
12.
This question is about a nuclear reactor.
(a)
Uranium is used as a fuel in a small research nuclear reactor. The concentration of
in a sample of uranium must be increased before it can be used as a fuel.
State the name of the process by which the concentration of
235
92 U
235
92 U
is increased.
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(1)
IB Questionbank Physics
11
(b)
The reactor produces 24 MW of power. The efficiency of the reactor is 32 %. In the
fission of one uranium-235 nucleus 3.2 × 10–11 J of energy is released.
Determine the mass of uranium-235 that undergoes fission in one year in this reactor.
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(4)
(c)
Explain what would happen if the moderator of this reactor were to be removed.
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(3)
(d)
During its normal operation, the following set of reactions takes place in the reactor.
1
238
239
0 n  92 U  92 U
239
239
0
92 U  93 Np  –1 e  v
239
239
0
93 Np  94Pu  –1e  v
(i)
(I)
(II)
(III)
State the name of the process represented by reaction (II).
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(1)
IB Questionbank Physics
12
(ii)
Comment on the international implications of the product of these reactions.
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(2)
(Total 11 marks)
13.
This question is about the energy balance of the Earth.
(a)
The intensity of the Sun’s radiation at the position of the Earth is approximately
1400 W m–2.
Suggest why the average power received per unit area of the Earth is 350 W m–2.
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(2)
IB Questionbank Physics
13
(b)
The diagram shows a simplified model of the energy balance of the Earth’s surface.
The diagram shows radiation entering or leaving the Earth’s surface only.
The average equilibrium temperature of the Earth’s surface is TE and that of the
atmosphere is TA = 242 K.
(i)
Using the data from the diagram, state the emissivity of the atmosphere.
...........................................................................................................................
(1)
(ii)
Show that the intensity of the radiation radiated by the atmosphere towards the
Earth’s surface is 136 W m–2.
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(1)
IB Questionbank Physics
14
(iii)
By reference to the energy balance of the Earth’s surface, calculate TE.
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(2)
(c)
(i)
Outline a mechanism by which part of the radiation radiated by the Earth’s surface
is absorbed by greenhouse gases in the atmosphere.
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(3)
(ii)
Suggest why the incoming solar radiation is not affected by the mechanism you
outlined in (c)(i).
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(2)
IB Questionbank Physics
15
(iii)
Carbon dioxide (CO2) is a greenhouse gas. State one source and one sink (object
that removes CO2) of this gas.
Source: ..............................................................................................................
Sink: ..................................................................................................................
(2)
(Total 13 marks)
14.
Surface X has a temperature TX and emissivity εx. Surface Y has a temperature TY and
emissivity εy. The two surfaces emit radiation at the same rate.
What is the ratio
TX
?
TY
1
A.
y


 x
4



B.
x

y

4







4
C.
y


 x




4
D.
X

y

1
(Total 1 mark)
IB Questionbank Physics
16
15.
Large areas of rainforests are cut down and burned every year. The result of these actions is
A.
reduced albedo.
B.
reduced carbon fixation.
C.
increased evaporation rate.
D.
increased mass of atmospheric methane.
(Total 1 mark)
16.
This question is about power production and global warming.
(a)
In any cyclical process designed to continuously convert thermal energy to work, some
energy is always degraded. Explain what is meant by degraded energy.
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(2)
(b)
A nuclear power station uses uranium-235 (U-235) as fuel. Outline the
(i)
processes and energy changes that occur through which thermal energy is
produced.
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(4)
IB Questionbank Physics
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(ii)
role of the heat exchanger of the reactor and the turbine in the generation of
electrical energy.
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(3)
(c)
Identify one process in the power station where energy is degraded.
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(1)
(d)
The maximum power output of the Drax coal-fired power station in the UK is 4.0 GW.
Determine the minimum mass of pure U-235 that would be required by a nuclear power
station to provide the same maximum annual energy output as the Drax power station.
Energy density of U-235 = 82 TJ kg–1
1 year
= 3.2 × 107 s
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(2)
IB Questionbank Physics
18
(e)
The Drax power station produces an enormous amount of carbon dioxide, a gas classified
as a greenhouse gas. Outline, with reference to the vibrational behaviour of molecules of
carbon dioxide, what is meant by a greenhouse gas.
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(3)
(f)
It has been suggested that the production of greenhouse gases by coal-fired power stations
has increased global warming. One piece of evidence to support this suggestion is the
increase in sea-level due to an increase in temperature of the oceans. Over the past 100
years it is suggested that sea-levels have risen by 6.4 × 10–2 m due to volume expansion.
Using the following data, determine the average rise in temperature in the top levels of
the oceans in the last 100 years.
Mean depth of oceans that is affected by global warming
Coefficient of volume expansion of sea water
= 4.0 × 102 m
= 5.1 × 10–5 K–1
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(3)
(Total 18 marks)
IB Questionbank Physics
19
17.
This question is about solar radiation.
(a)
State the Stefan–Boltzmann law for a black body.
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......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(b)
The following data relates to the Earth and the Sun.
Earth-Sun distance
radius of Earth
radius of Sun
surface temperature of Sun
(i)
= 1.5 × 1011 m
= 6.4 × 106 m
= 7.0 × 108 m
= 5800 K
Use data from the table to show that the power radiated by the Sun is about
4 × 1026 W.
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...........................................................................................................................
(1)
(ii)
Calculate the solar power incident per unit area at a distance from the Sun equal to
the Earth’s distance from the Sun.
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(2)
IB Questionbank Physics
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(iii)
The average power absorbed per unit area at the Earth’s surface is 240 W m–2.
State two reasons why the value calculated in (b)(ii) differs from this value.
1: .......................................................................................................................
...........................................................................................................................
2: .......................................................................................................................
...........................................................................................................................
(2)
(iv)
Show that the value for power absorbed per unit area of 240 W m–2 is consistent
with an average equilibrium temperature for the Earth of about 255 K.
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...........................................................................................................................
...........................................................................................................................
(2)
(c)
Explain, by reference to the greenhouse effect, why the average temperature of the
surface of the Earth is greater than 255 K.
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(3)
IB Questionbank Physics
21
(d)
Suggest why the burning of fossil fuels may lead to an increase in the temperature of the
surface of the Earth.
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(3)
(Total 15 marks)
18.
This question is about fossil fuels and the greenhouse effect.
(a)
State two reasons why most of the world’s energy consumption is provided by fossil
fuels.
1. ..................................................................................................................................
......................................................................................................................................
2. ..................................................................................................................................
......................................................................................................................................
(2)
(b)
A power station has an output power of 500 MW and an overall efficiency of 27 %.
It uses natural gas as a fuel that has an energy density of 56 MJ kg–1.
(i)
Define energy density.
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(1)
IB Questionbank Physics
22
(ii)
Determine the rate of consumption of natural gas in the power station.
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(3)
(c)
Outline why the enhanced greenhouse effect may result in an increase in the temperature
of the Earth’s surface.
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......................................................................................................................................
(3)
(d)
(i)
The solar intensity at the position of the Earth is 1380 W m–2. The average albedo
of Earth is 0.300. State why an average value of albedo is quoted.
...........................................................................................................................
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(1)
IB Questionbank Physics
23
(ii)
Show that the average reflected intensity from the Earth is about 100 W m–2.
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...........................................................................................................................
(4)
(e)
One of the expected results of global warming is an increased sea level. The increase in
volume ΔV for a temperature increase ΔT is given by ΔV = γVΔT. Show, using the
following data, that the resulting rise in sea level is about 0.5 m.
Temperature increase
Surface area of oceans on Earth
Average ocean depth
γ
= 2.0 °C
= 3.6 × 108 km2
= 3.0 km
= 8.8 × 10–5 K–1
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(2)
(Total 16 marks)
IB Questionbank Physics
24
19.
This question is about the production of energy in nuclear fission.
(a)
A possible fission reaction is
235
92 U
(i)
141
1
 01n 92
36 Kr  56 Ba  x 0 n .
State the value of x.
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
Show that the energy released when one uranium nucleus undergoes fission in the
reaction in (a) is about 2.8 × 10–11 J.
Mass of neutron
Mass of U-235 nucleus
Mass of Kr-92 nucleus
Mass of Ba-141 nucleus
= 1.00867 u
= 234.99333 u
= 91.90645 u
= 140.88354 u
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...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(4)
(iii)
State how the energy of the neutrons produced in the reaction in (a) is likely to
compare with the energy of the neutron that initiated the reaction.
...........................................................................................................................
...........................................................................................................................
(1)
IB Questionbank Physics
25
(b)
Outline the role of the moderator.
......................................................................................................................................
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......................................................................................................................................
......................................................................................................................................
(2)
(c)
A nuclear power plant that uses U-235 as fuel has a useful power output of 16 MW and
an efficiency of 40 %. Assuming that each fission of U-235 gives rise to 2.8 × 10–11 J of
energy, determine the mass of U-235 fuel used per day.
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(4)
(Total 12 marks)
20.
This question is about energy transfers.
(a)
Energy degradation takes place in the energy transformations which occur in the
generation of electrical power. Explain what is meant in this context by energy
degradation.
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......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
IB Questionbank Physics
26
Some of the energy transformations that take place in a coal-fired power station are represented
by the Sankey diagram below.
(b)
(i)
State what is represented by the width w.
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
At the three places marked A, B and C on the diagram, energy is degraded.
Identify the process by which the energy is degraded in each of the places.
A: ......................................................................................................................
...........................................................................................................................
B: ......................................................................................................................
...........................................................................................................................
C: ......................................................................................................................
...........................................................................................................................
(3)
(Total 6 marks)
IB Questionbank Physics
27
21.
This question is about greenhouse effect
(a)
The graph shows part of the absorption spectrum of nitrogen oxide (N2O) in which the
intensity of absorbed radiation A is plotted against frequency f.
(i)
State the region of the electromagnetic spectrum to which the resonant frequency
of nitrogen oxide belongs.
...........................................................................................................................
(1)
(ii)
Using your answer to (a)(i), explain why nitrogen oxide is classified as a
greenhouse gas.
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...........................................................................................................................
(2)
IB Questionbank Physics
28
(b)
Define emissivity and albedo.
Emissivity: ...................................................................................................................
......................................................................................................................................
Albedo: ........................................................................................................................
......................................................................................................................................
(3)
(c)
The diagram shows a simple energy balance climate model in which the atmosphere and
the surface of Earth are two bodies each at constant temperature. The surface of the Earth
receives both solar radiation and radiation emitted from the atmosphere. Assume that the
Earth’s surface behaves as a black body.
The following data are available for this model.
average temperature of the atmosphere of Earth
emissivity, e of the atmosphere of Earth
average albedo, α of the atmosphere of Earth
solar intensity at top of atmosphere
average temperature of the surface of Earth
IB Questionbank Physics
= 242 K
= 0.720
= 0.280
= 344 W m–2
= 288 K
29
Use the data to show that the
(i)
power radiated per unit area of the atmosphere is 140 W m–2.
...........................................................................................................................
...........................................................................................................................
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...........................................................................................................................
...........................................................................................................................
(2)
(ii)
solar power absorbed per unit area at the surface of the Earth is 248 W m–2.
...........................................................................................................................
...........................................................................................................................
(1)
(d)
It is hypothesized that, if the production of greenhouse gases were to stay at its present
level then the temperature of the Earth’s atmosphere would eventually rise by 6.0 K.
Calculate the power per unit area that would then be
(i)
radiated by the atmosphere.
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
absorbed by the Earth’s surface.
...........................................................................................................................
...........................................................................................................................
(1)
IB Questionbank Physics
30
(e)
Estimate, using your answer to (d)(ii), the increase in temperature of Earth’s surface.
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......................................................................................................................................
......................................................................................................................................
(3)
(Total 14 marks)
22.
This question is about fossil fuels.
(a)
A Sankey diagram for the generation of electrical energy using fossil fuel as the primary
energy source is shown.
(i)
State what is meant by a fuel.
...........................................................................................................................
...........................................................................................................................
(1)
IB Questionbank Physics
31
(ii)
State two examples of fossil fuels.
1. .......................................................................................................................
2. .......................................................................................................................
(2)
(iii)
Explain why fossil fuels are said to be non-renewable.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(iv)
Use the Sankey diagram to estimate the efficiency of production of electrical
energy and explain your answer.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
IB Questionbank Physics
32
(b)
Despite the fact that fossil fuels are non-renewable and contribute to atmospheric
pollution there is widespread use of such fuels. Suggest three reasons for this widespread
use.
1. ..................................................................................................................................
......................................................................................................................................
2. ..................................................................................................................................
......................................................................................................................................
3. ..................................................................................................................................
......................................................................................................................................
(3)
(Total 10 marks)
23.
This question is about wave power.
(a)
Outline how the energy of a wave can be converted to electrical energy.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(b)
A wave on the surface of water is assumed to be a square-wave of height 2A, as shown.
IB Questionbank Physics
33
The wave has wavelength λ, speed v and has a wavefront of length L. For this wave,
(i)
show that the gravitational potential energy EP stored in one wavelength of the
wave is given by
EP =
1
2
A 2 gL
where ρ is the density of the water and g is the acceleration of free fall.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(ii)
deduce that the gravitational wave power P per unit length of the wavefront is
given by
P=
1
2
A2vg ρ
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(c)
The density of sea-water is 1.2 × 103 kg m–3. Using the expression in (b)(ii), estimate the
gravitational power per metre length available in a wave of height 0.60 m.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
IB Questionbank Physics
34
(d)
In practice a water wave is approximately sinusoidal in cross-section. Outline whether a
sine wave of the same height as in (b) transfers a greater or a smaller amount of power
than that derived in (b)(ii).
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(e)
List two advantages of the utilization of wave power rather than photovoltaic cells for the
generation of electric power.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(Total 13 marks)
24.
This question is about the albedo of the Earth.
(a)
Outline the mechanism by which a gas, such as carbon dioxide, absorbs infra-red
radiation.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(b)
State, with reference to your answer in (a), why carbon dioxide is known as a greenhouse
gas.
......................................................................................................................................
......................................................................................................................................
(1)
IB Questionbank Physics
35
(c)
State the name of another greenhouse gas.
......................................................................................................................................
(1)
(d)
In the last fifty years the amount of carbon dioxide in the Earth’s atmosphere has
increased significantly. Explain
(i)
why this increase could account for global warming.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
what effect this has had on the average albedo of the Earth.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
IB Questionbank Physics
36
(e)
It has been estimated that doubling the amount of carbon dioxide in the Earth’s
atmosphere changes the albedo of the Earth by 0.01. Use the data to show that this
doubling will lead to a change of about 3 W m–2 in the intensity being reflected by the
Earth into space.
Average intensity received at Earth from the Sun = 340 W m–2
Average albedo = 0.30
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(3)
(f)
State one reason why the answer to (e) is an estimate.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(1)
(Total 12 marks)
IB Questionbank Physics
37
25.
This question is about a pumped-storage power station.
(a)
The diagram, not to scale, shows a pumped-storage power station used for the generation
of electrical energy.
Water stored in the tank is allowed to fall through a pipe to a lake via a turbine. The
turbine is connected to an electrical generator. The pumped-storage ac generator system is
reversible so that water can be pumped from the lake to the tank.
The tank is 50 m deep and has a uniform area of 5.0 × 104 m2. The height from the
bottom of the tank to the turbine is 310 m. The density of water is 1.0 × 103 kg m–3.
(i)
Show that the maximum energy that can be delivered to the turbine by the falling
water is about 8 × 1012 J.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(ii)
The flow rate of water in the pipe is 400 m3 s–1. Calculate the power delivered by
the falling water.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
IB Questionbank Physics
38
(b)
The energy losses in the power station are shown in the following table.
Source of energy loss
Percentage loss of energy
friction and turbulence of water in pipe
27
friction in turbine and ac generator
15
electrical heating losses
5
(i)
Calculate the overall efficiency of the conversion of the gravitational potential
energy of water in the tank into electrical energy.
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
Sketch a Sankey diagram to represent the energy conversion in the power station.
(2)
(c)
The electrical power produced at the power station is transmitted by cables to the
consumer.
(i)
Outline how the energy losses in transmission are minimized.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
IB Questionbank Physics
39
(ii)
State one advantage and one disadvantage that a pumped-storage system has
compared to a tidal water storage system.
Advantage: .......................................................................................................
...........................................................................................................................
Disadvantage: ...................................................................................................
...........................................................................................................................
(2)
(Total 13 marks)
26.
This question is about global warming.
(a)
One reason often suggested for global warming is the enhanced greenhouse effect.
(i)
State what is meant by the enhanced greenhouse effect.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
State two other possible causes of global warming.
1. .......................................................................................................................
...........................................................................................................................
2. .......................................................................................................................
...........................................................................................................................
(2)
(b)
One effect of global warming is to melt the Antarctic ice sheet. The following data are
available for the Antarctic ice sheet and the Earth’s oceans.
Area of ice sheet
Average thickness of ice
Density of ice
Density of water
Area of Earth’s oceans
IB Questionbank Physics
= 1.4 × 107 km2
= 1.5 × 103 m
= 920 kg m–3
= 1000 kg m–3
= 3.8 × 108 km2
40
Using the data, determine the
(i)
mass of the Antarctic ice.
...........................................................................................................................
...........................................................................................................................
(2)
(ii)
change in mean sea level if all the Antarctic ice sheet were to melt and flow into
the oceans.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(c)
Outline the difference, if any, that the melting of oceanic ice sheets makes to the mean
sea level of the Earth.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
(2)
(Total 10 marks)
IB Questionbank Physics
41
27.
This question is about the electrical power available from a wind turbine.
The maximum electrical power generated by a wind turbine, Pout, was measured over a range of
incident wind speeds, vin.
The graph below shows the variation with vin of Pout. Uncertainties for the data are not shown.
(a)
It is suggested that Pout is proportional to
(i)
v in .
Draw the line of best-fit for the data points.
(1)
(ii)
State one reason why the line you have drawn does not support this hypothesis.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(1)
(iii)
The uncertainty in the power at 15 m s–1 is 5 . Draw an error bar on the graph to
represent this uncertainty.
(2)
IB Questionbank Physics
42
(b)
The theoretical relationship between the available power in the wind, Pin, and incident
wind speed is shown in the graph below.
4000
3500
3000
2500
Pm / kW
2000
1500
1000
500
0
0
5
10
15
20
25
Vm / ms–1
Using both graphs,
(i)
determine the efficiency of the turbine for an incident wind speed of 14 m s–1.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(3)
IB Questionbank Physics
43
(ii)
suggest, without calculation, how the efficiency of the turbine changes with
increasing wind speed.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(3)
(c)
Outline one advantage and one disadvantage of using wind turbines to generate electrical
energy.
Advantage:
...................................................................................................
...................................................................................................
...................................................................................................
...................................................................................................
Disadvantage: ...................................................................................................
...................................................................................................
...................................................................................................
...................................................................................................
(2)
(Total 12 marks)
28.
Simple harmonic motion and the greenhouse effect
(a)
A body is displaced from equilibrium. State the two conditions necessary for the body to
execute simple harmonic motion.
1.
.........................................................................................................................
.........................................................................................................................
2.
.........................................................................................................................
.........................................................................................................................
(2)
IB Questionbank Physics
44
(b)
In a simple model of a methane molecule, a hydrogen atom and the carbon atom can be
regarded as two masses attached by a spring. A hydrogen atom is much less massive than
the carbon atom such that any displacement of the carbon atom may be ignored.
The graph below shows the variation with time t of the displacement x from its
equilibrium position of a hydrogen atom in a molecule of methane.
The mass of hydrogen atom is 1.7  10–27 kg. Use data from the graph above
(i)
to determine its amplitude of oscillation.
.........................................................................................................................
(1)
(ii)
to show that the frequency of its oscillation is 9.1  1013 Hz.
.........................................................................................................................
.........................................................................................................................
(2)
IB Questionbank Physics
45
(iii)
to show that the maximum kinetic energy of the hydrogen atom is 6.2  10–18 J.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(2)
(c)
On the grid below, sketch a graph to show the variation with time t of the velocity v of the
hydrogen atom for one period of oscillation starting at t = 0. (There is no need to add
values to the velocity axis.)
(3)
(d)
Assuming that the motion of the hydrogen atom is simple harmonic, its frequency of
oscillation f is given by the expression
f
1
2
k
,
mp
where k is the force per unit displacement between a hydrogen atom and the carbon atom
and mp is the mass of a proton.
(i)
Show that the value of k is approximately 560 N m–1.
.........................................................................................................................
.........................................................................................................................
(1)
IB Questionbank Physics
46
(ii)
Estimate, using your answer to (d)(i), the maximum acceleration of the hydrogen
atom.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(2)
(e)
Methane is classified as a greenhouse gas.
(i)
Describe what is meant by a greenhouse gas.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(2)
(ii)
Electromagnetic radiation of frequency 9.1  1013 Hz is in the infrared region of
the electromagnetic spectrum. Suggest, based on the information given in (b)(ii),
why methane is classified as a greenhouse gas.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(2)
(Total 17 marks)
IB Questionbank Physics
47
29.
This question is about nuclear power production.
(a)
The purpose of a nuclear power station is to produce electrical energy from nuclear
energy. The diagram below is a representation of the principal components of a nuclear
reactor pile used in a certain type of nuclear power station that uses uranium as a fuel.
The function of the moderator is to slow down the neutrons produced in a reaction such
as that described above.
Explain,
(i)
why it is necessary to slow down the neutrons.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(3)
(ii)
the function of the control rods.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(2)
IB Questionbank Physics
48
(b)
With reference to the concept of fuel enrichment in a nuclear reactor explain,
(i)
the advantage of enriching the uranium used in a nuclear reactor.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(3)
(ii)
from an international point of view, a possible risk to which fuel enrichment could
lead.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(2)
(c)
A particular nuclear reactor uses uranium-235 as its fuel source. When a nucleus of
uranium-235 absorbs a neutron, the following reaction can take place.
235
92
U  01 n  144
54 Xe 
90
38
Sr  2 01 n
The following data are available.
IB Questionbank Physics
rest mass of
235
92
U = 2.1895  105 MeV c–2
rest mass of
144
54
Xe = 1.3408  105 MeV c–2
rest mass of
90
38
rest mass of
1
0
Sr = 8.3749  104 MeV c–2
n = 939.56 MeV c–2
49
(i)
Show that the energy released in the reaction is approximately 180 MeV.
.........................................................................................................................
.........................................................................................................................
(1)
(ii)
State the form in which the energy appears.
.........................................................................................................................
(1)
(d)
The energy released by 1 atom of carbon-12 during combustion is approximately 4 eV.
(i)
Using the answer to (c)(i), estimate the ratio
energy density of uranium -235
.
energy density of carbon-12
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(3)
(ii)
Suggest, with reference to your answer in (d)(i), one advantage of uranium-235
compared with fossil fuels.
.........................................................................................................................
.........................................................................................................................
(1)
IB Questionbank Physics
50
(e)
When a uranium-238 nucleus absorbs a neutron the following reaction can take place.
238
92
U  01 n 
239
92
U
The isotope uranium-239 is radioactive and decays with a half-life of 23 minutes to form
an isotope of neptunium-239 (Np-239).
(i)
Define radioactive half-life and explain what is meant by an isotope.
Radioactive half-life:
.........................................................................................................................
.........................................................................................................................
Isotope:
.........................................................................................................................
.........................................................................................................................
(2)
(ii)
Complete the reaction equation for this decay.
239
92
U
(3)
IB Questionbank Physics
51
(iii)
The isotope neptunium-239 undergoes radioactive  decay to form an isotope of
plutonium. Outline one advantage and one disadvantage of this decay in relation to
nuclear power production.
Advantage:
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
Disadvantage:
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(4)
(Total 25 marks)
30.
This question is about fuel for heating.
(a)
Define the energy density of a fuel.
......................................................................................................................................
......................................................................................................................................
(1)
(b)
A room heater burns liquid fuel and the following data are available.
Density of liquid fuel
Energy produced by 1 m3 of liquid fuel
Rate at which fuel is consumed
Latent heat of vaporization of the fuel
IB Questionbank Physics
= 8.0 × 102 kg m–3
= 2.7 × 1010 J
= 0.13 g s–1
= 290 kJ kg–1
52
(i)
Use the data to calculate the power output of the room heater, ignoring the power
required to convert the liquid fuel into a gas.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(ii)
Show why, in your calculation in (b)(i), the power required to convert the liquid
fuel into a gas at its boiling point can be ignored.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(c)
State, in terms of molecular structure and their motion, two differences between a liquid
and a gas.
1. ..................................................................................................................................
......................................................................................................................................
2. ..................................................................................................................................
......................................................................................................................................
(2)
(Total 8 marks)
IB Questionbank Physics
53
31.
This question is about internal energy, heat and ideal gases.
(a)
The internal energy of a piece of copper is increased by heating.
(i)
Explain what is meant, in this context, by internal energy and heating.
Internal energy: .................................................................................................
...........................................................................................................................
...........................................................................................................................
Heating: ............................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(ii)
The piece of copper has mass 0.25 kg. The increase in internal energy of the copper
is 1.2 × 103 J and its increase in temperature is 20 K. Estimate the specific heat
capacity of copper.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(b)
An ideal gas is kept in a cylinder by a piston that is free to move. The gas is heated such
that its internal energy increases and the pressure remains constant. Use the molecular
model of ideal gases to explain
(i)
the increase in internal energy.
...........................................................................................................................
...........................................................................................................................
(1)
IB Questionbank Physics
54
(ii)
how the pressure remains constant.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(Total 9 marks)
32.
This question is about thermal energy transfer.
(a)
A piece of copper is held in a flame until it reaches thermal equilibrium. The time it takes
to reach thermal equilibrium will depend on the thermal capacity of the piece of copper.
(i)
Define thermal capacity.
...........................................................................................................................
...........................................................................................................................
(1)
(ii)
Outline what is meant by thermal equilibrium in this context.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(1)
(b)
The piece of copper is transferred quickly to a plastic cup containing water. The thermal
capacity of the cup is negligible. The following data are available.
Mass of copper
Mass of water
Rise in temperature of water
Final temperature of copper
Specific heat capacity of copper
Specific heat capacity of water
IB Questionbank Physics
= 0.12 kg
= 0.45 kg
= 30 K
= 308 K
= 390 J kg K–1
= 4200 J kg K–1
55
(i)
Use the data to calculate the temperature of the flame.
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(3)
(ii)
Explain whether the temperature of the flame is likely to be greater or less than
your answer to (b)(i).
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(Total 7 marks)
33.
Specific heat and a domestic shower
(a)
Define specific heat capacity.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(1)
IB Questionbank Physics
56
(b)
Equal masses of two different solid substances A and B are at the same temperature. The
specific heat capacity of substance A is greater than the specific heat capacity of
substance B. The two substances now have their temperatures raised by the same amount.
Explain which substance will have the greater increase in internal energy assuming both
remain in the solid phase.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................
(2)
(c)
The diagram below shows part of the heating circuit of a domestic shower.
Cold water enters the shower unit and flows over an insulated heating element. The
heating element is rated at 7.2 kW, 240 V. The water enters at a temperature of 14 C and
leaves at a temperature of 40 C. The specific heat capacity of water is
4.2  103 J kg–1 K–1.
(i)
Estimate the flow rate of the water.
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
.........................................................................................................................
(4)
IB Questionbank Physics
57
(ii)
Suggest one reason why your answer to (c)(i) is only an estimate.
.........................................................................................................................
.........................................................................................................................
(1)
(Total 8 marks)
IB Questionbank Physics
58