Syllabus Edition

First teaching 2014

Last exams 2024

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Energy Sources (DP IB Physics: SL)

Exam Questions

4 hours45 questions
1a
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4 marks

A manufacturing company is looking to revolutionise the way water can be heated in the home. Fuels can be compared using energy density and specific energy.

Match, by drawing a line, energy density and specific energy to the quantity they compare and their units.

8-1-ib-sl-sq1a-q-easy
1b
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3 marks

Kerosene is a clean and cost−effective energy source for heating water. The specific energy of Kerosene is 48 × 106 J kg−1 and the energy density is 3.3 × 1010 J m−3

D e n s i t y space equals space fraction numerator E n e r g y space d e n s i t y over denominator S p e c i f i c space e n e r g y end fraction

Calculate the density of Kerosene.

1c
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3 marks

A new kettle is being developed that claims to be 75% efficient. 

Sketch a Sankey diagram on the squares below to represent this situation. 

8-1-q1c-sl-sq-easy-phy
1d
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2 marks

In a new prototype kettle, claimed to be 95% efficient, 300 000 J of energy is required to raise the temperature of the full kettle of water from room temperature to boiling point. 

Calculate the amount of energy wasted by the kettle.

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2a
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3 marks

An energy company is analysing their energy sources to provide cheaper and greener energy to its customers.

Define a primary energy source.

2b
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2 marks

The energy company are considering using more nuclear power to generate their electricity. 

State whether nuclear fission is a renewable or non-renewable energy source and give a reason for your answer.

2c
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4 marks

The energy company is trying to improve its understanding of nuclear energy.

Identify four advantages of using nuclear power by placing a tick () next to the correct statements in the table below. 

  There are extensive reserves of fissionable materials
  Nuclear power is always sustainable and will never run out
  The technology to extract the fissionable material from the rocks is improving
  No greenhouse gases are produced from a nuclear reactor
  Nuclear waste is easy to dispose
  A large amount of power can be produced from a small amount of fissionable material

2d
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3 marks

The energy company is investigating the purpose of the control rods, the moderator and the shielding within a nuclear reactor. 

Place a tick (✔) in the correct box to show the purpose of each part of the nuclear reactor. 

 

Control Rods

Moderator

Shielding

Absorb hazardous radiation

     

Slow down neutrons

     

Absorb neutrons

     

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3a
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2 marks

A developer looking to create a new residential complex is analysing the energy required for the construction of the project. She is investigating the differences between primary and secondary energy sources. 

The following statements are about secondary energy sources. Place a tick (✔) next to the correct statement(s).

 

Statement is correct

Wind power is an example of a secondary energy source

 

Secondary energy sources come from the use or processing of primary energy sources

 

Examples of secondary energy sources are geothermal, hydroelectric and solar power

 

An example of a secondary energy source includes converting the gravitational potential energy from falling water into electricity

 

3b
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4 marks

The developer is also trying to identify which energy resources are renewable and which are non-renewable. 

Identify whether the energy resources below are renewable or non-renewable. Place a tick (✔) in the correct for each resource.

 

Renewable Resources

Non-Renewable Resources

Petrol

   

Solar Energy

   

Wind

   

Coal

   

Nuclear Fission

   

Tidal

   

Natural Gas

   

Bio-Fuel

   

3c
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3 marks

The developer is investigating the set-up of a nuclear power plant. 

Identify the key components of the nuclear reactor by adding the following labels to the diagram:

  • Control Rods
  • Graphite Moderator
  • Radiation Shielding

8-1-ib-sl-sq3c-q-easy

3d
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3 marks

The developer is impressed by the amount of electricity that can be generated in a nuclear reactor with a small amount of uranium. They are concerned, however, with the safety of workers within a nuclear power plant. 

With the aid of the diagram supplied below, identify three safety features designed to reduce workers' exposure to radiation. 

8-1-ib-sl-sq3d-q-easy

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4a
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3 marks

A farmer has been approached by the National Grid asking if they can install wind turbines on part of his land. 

Identify the following components of the wind turbine by labelling the diagram below: 

  • Rotor blade
  • Generator
  • Gear Box

8-1-ib-sl-sq4a-q-easy

4b
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3 marks

The National Grid are really keen to use the farmer's land for wind turbines because of the consistently high wind speed available. The density of the surrounding air is 1.32 kg m−3 and its velocity is 12 m s−1. The cross-sectional area of the column of air that would be incident on one wind turbine is 125 000 m2.

Calculate the maximum power possible in this situation and put your answer in standard form.

4c
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4 marks

The farmer would prefer not to have wind turbines on his land. He is keen to support the motion for an extension to be made to the local coal-fired power station instead. 

The following statements are advantages or disadvantages of using a coal-fired power station to generate electricity. Place a tick (✔) next to the correct statement(s) to say whether they are advantages or disadvantages. 

 

Advantage

Disadvantage

Produces greenhouse gases

   

High energy density of fuel

   

Available at any time

   

Non-renewable

   

Produces pollution

   

Long established method for generating electricity

   

Extensive infrastructure already in place

   

4d
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3 marks

The National Grid are continually assessing the main uses of energy and the types of energy resources used to generate them. 

Identify the types of energy resources used for transport, electricity generation and heating by drawing lines between them. 

Each energy resource may be used up to a maximum of two times.

8-1-ib-sl-sq4d-q-easy

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5a
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3 marks

Nepal is a mountainous country, making it ideal for using hydroelectric power to generate electricity. 

Use the text in the box to complete the sentences below, identifying the conditions needed for hydroelectric power.

gravitational potential energy depth dropped
Kinetic energy height pumped

   
(i)
Water needs to be stored at ____________.
[1]
(ii)
______________ energy is released.
[1]
(iii)
Water is __________ from a height to turn the turbines of a generator.
[1]
5b
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4 marks

A location in the Annapurna region of Nepal is being analysed for its suitability as a new hydroelectric power station. The plan is to have water of density 1000 kg m−3 flowing at a rate of 150 × 10−3 ms−1 through a turbine that then descends a distance of 380 m.

Calculate the maximum power obtained from this system.

5c
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3 marks

Most people in cities in Nepal have solar panels on their roof to generate electricity for their household. 

Identify three advantages of using solar panels in countries like Nepal where there is bright sunlight for a large portion of the day. 

5d
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4 marks

The Nepali government are putting together a flyer to explain to people how solar panels work. 

On the diagram below label the following: 

  • Electrode
  • Reflect-proof film
  • N-type semiconductor
  • P-type semiconductor

8-1-ib-sl-sq5d-q-easy

5e
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4 marks

On the second page of the flyer, the Nepali government wants to have a clear description of the function of each part of the solar panel. 

Draw a line between the correct component of the solar panel and its function. 

8-1-ib-sl-sq5e-q-easy

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1a
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2 marks

A tidal power station traps water when the tide rises above the level of the power station turbines. The trapped water is released in a controlled manner over a period of 7 hours.

The following data are available:

Difference between high and low tide water level = 3.0 m
Density of sea water = 1.1 × 103 kg m–3
Area of tidal basin = 250 km2
Overall efficiency of power station = 24% 

Calculate the mass of trapped water.

1b
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3 marks

Determine the average loss of potential energy per second over the seven hours of controlled release of water.

1c
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3 marks

For the tidal power station: 

(i)
Calculate the electrical power generated between successive high and low tides.

[2]

(ii)
Identify one mechanism through which energy is transferred to the surroundings during the electricity generation process.

[1]

1d
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2 marks

A certain proportion of the water’s gravitational potential energy is transferred to the surroundings.

i)
State the term used to describe energy which has been transferred in this way.

[1]
ii)
Explain the meaning of the term stated in part (i).
[1]

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2a
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4 marks

A horizontal-axis wind turbine with blades of length 12 m is sited in an area which has a reasonably constant average wind speed of 13 m s–1 for significant parts of the day.

Calculate the average mass of air per second that passes through the area swept out by the blades of the turbine. Assume the density of air = 1.2 kg m−3.

2b
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3 marks

The power which is available from this turbine is about 36% of the kinetic energy per second of the incident wind.

Calculate the output power available, in watts, at this wind speed from this generator.  

2c
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5 marks

Outline the construction and operation of a horizontal-axis wind generator, by: 

(i)
Stating the main components and arrangement of the wind turbine

[3]

(ii)
Discussing the energy conversions in the machinery of the turbine and the generator.

[2]

2d
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3 marks
The total incident kinetic energy incident on a rotating turbine driven by the wind can never be fully converted to rotational kinetic energy of the blades.

Discuss reasons why this is the case. 

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3a
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3 marks

The Sizewell B Pressurised Water Reactor (PWR) in the UK uses Uranium-235 as fuel and water as both coolant and steam to drive a generator.

Outline the processes which lead to the production of thermal energy in the PWR.

3b
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4 marks

A nuclear reactor has several key components. In generating electricity, outline the role of the:

(i)
Heat exchanger of a PWR

[2]

(ii)
Turbine and generator.

[2]

3c
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4 marks

Uranium–235 is the primary energy source in the PWR. It has an energy density in the region of 1.3 × 1018 J m–3 and a specific energy of 7.0 × 1013J kg–1.

(i)
Explain the terms primary energy source and energy density.

[2]

(ii)
Calculate the density of uranium-235.

[2]

3d
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3 marks
In the nuclear reactor the number of uranium–235 nuclei undergoing fission per second is 8.70 × 1020. Each fission gives rise to 250 MeV of energy which is available to be converted to electrical energy by the power station.

If the overall efficiency of the power station is 37%, calculate the power output of the power station.

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4a
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3 marks
A remote community requires a peak power of 900 kW. Two systems are available for energy generation: photovoltaic cells for electrical energy and a power station burning waste material as its source of heat.

The diagram shows an arrangement of eight photovoltaic cells, which forms a single module. Each cell in the module has an emf of 0.75 V and an internal resistance of 1.9 Ω.

q4a_energy-sources_ib-sl-physics-sq-medium-1

For the module, calculate:

(i)
the total emf

[1]

(ii)
the total internal resistance.

[2]

4b
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3 marks

The intensity of solar radiation incident on the module is 3.5 × 102 W m−2. The photovoltaic cells are 22% efficient.

Calculate the minimum area required per module to fulfil the community’s energy needs.

4c
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4 marks

The Sankey diagram shows the energy flow in a power station burning waste material to convert to heat which is then supplied through pipes to the homes and businesses of the local community.


AyGBnazh_q4c_energy-sources_ib-sl-physics-sq-medium

For the power station: 

(i)
determine its efficiency

[2]

(ii)
identify the primary and secondary energy sources.

[2]

4d
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2 marks

Another mechanism of heating water for use in the home uses solar heating panels.

Distinguish between a photovoltaic cell and a solar heating panel by referring to the operation of each and the energy transformations involved.

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5a
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3 marks

Pumped hydroelectric systems store water behind a dam. When electricity is needed in the grid the water is released to turn a turbine.

The system shown has an upper reservoir 42 m in depth when full and allows water to fall a vertical distance of 396 m before reaching the turbine.


q5a_energy-sources_ib-sl-physics-sq-medium

Estimate the specific energy of the water held in the reservoir.

5b
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4 marks

Water is made to flow out of the upper reservoir through connecting pipes at a rate of 12 000 m3 per minute. The density of water is 1.0 × 103 kg m−3

Calculate the transfer rate of gravitational potential energy of the water stored in the reservoir.

5c
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4 marks

The pumped storage system produces 0.62 GW of power and it can operate continuously for 22 hours before the water in the upper reservoir is depleted.

For the pumped storage system:

(i)
calculate its efficiency

[1]

(ii)
calculate the total energy supplied by the system

[2]

(iii)
state an assumption you made to calculate part (ii).

[1]

5d
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3 marks

After the upper reservoir is drained it is refilled with water from the lower reservoir. Pumping this water uphill requires energy. 

Explain how the operating company makes a profit on the energy they sell to the National Grid.

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1a
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4 marks

A new model wind turbine has a blade of length 6000 cm and is positioned offshore where the wind speed is an average of 4.2 km hr−1 and the air density is 1.2 × 10−6 g mm−3

sl-sq-8-1-hard-q1a

Calculate the number of wind turbines required in the wind farm to power a town of 30 million houses for 2 years. 

An average household consumes 28.8 kWh of electricity in 1 day. 

1b
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4 marks

Outline two assumptions made in calculating the power output of one turbine from part (a) and explain how each assumption simplifies your calculation. 

1c
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4 marks

Analyse the validity of the two assumptions made in part (b)

1d
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2 marks

In reality, wind turbines currently have a capacity factor of 60%

Capacity factor = fraction numerator a c t u a l italic space o u t p u t over denominator m a x i m u m italic space p o s s i b l e italic space o u t p u t end fraction

Calculate the average wind speed for the actual output of the turbine. 

1e
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3 marks

Show that the turbine is required to operate at the maximum possible wind speed for 14.4 hours a day to obtain a power output equivalent to the actual power output. 

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2a
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3 marks

A hydropower station in India has a semicircular dam of diameter 1.53 km and a depth of 53 m when full. The dam fills up during the monsoon season but is emptied at a steady rate over 8 days and 17 hours in the dry season. Water is released from the dam and falls a vertical distance of 305 m before reaching the turbine.   

The water has a density of 1.1 × 103 kg m−3 and the efficiency of the power station is 31%.

Calculate the electrical power generated by the release of the water from the dam. 

2b
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2 marks

Identify two ways that the hydropower station could increase its power output.

2c
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3 marks

The Indian government are deciding if hydroelectric power would be a viable energy source to supply electricity to every household in the city of Mumbai during the dry season.

Some data is shown in the table below.

Population of Mumbai City

23 million

Population of Mumbai Metropolitan Area

26 million

Average number of people per household in Mumbai City and Metropolitan areas

4.77

Average electricity consumption per household per day in Mumbai City

833 kWh

Average electricity consumption per household per day outside the city

417 kWh

Duration of the dry season

December to February

Average number of daylight hours in Mumbai per day

7 hours

The cost of building one dam 

790 million Indian Rupees

Using the data, calculate the number of dams that would be needed.

2d
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2 marks

Comment on the suitability for Mumbai to use hydropower as its main energy source during the dry season, and give reasons for your answer.

2e
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3 marks

Currently, 95% of the energy generated for the city of Mumbai comes from coal.

Suggest, with reasons, a cleaner and more sustainable alternative energy source for the Indian government to consider that would be more suitable for Mumbai. 

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3a
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3 marks

A small wind turbine with a blade length of 150 cm and an efficiency of 41% is situated in a field on the coast of Spain.

The air density at this location is 1200 g m−3. For 3.5 hours, the wind speed is 39.6 km hr−1 and for 1.25 hours, the wind speed is 14.4 km hr−1

Calculate the energy supplied by the wind turbine during this time.

3b
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2 marks

A solar panel with a surface area of 1.45 × 10−6 km2 and 44% efficiency is also present in the field.

The average intensity of sunlight received per day is 8.2 kWh m−2, assuming that this location receives sunlight for an average of 8.2 hours per day.

Compare the energy supplied by the solar panel and the wind turbine when operating for the same number of hours.

3c
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4 marks

The local council decide to install enough solar panels to power a village of 3500 houses. The average electricity consumption per household is 10.2 kWh per day. 

(i)
Calculate the number of solar panels needed to power the village for one day. 
[2]
(ii)
Suggest reasons the local council have chosen solar panels over wind turbines to power the village.
[2]

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4a
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3 marks

Pumped hydroelectric systems store water behind a dam. When electricity is needed in the grid the water is released to turn a turbine.

The system shown has an upper reservoir 42 m in depth when full and allows water to fall a vertical distance of 396 m before reaching the turbine.


q5a_energy-sources_ib-sl-physics-sq-medium

Water, with a density of 1.0 × 103 kg m−3, flows out of the reservoir at 1.5 × 1010 cm3 per minute. The pumped storage system produces 0.58 GW of power and can operate continuously for 19 hours and 27 minutes before the water in the upper reservoir is depleted. 

Calculate the efficiency, and hence, the total energy supplied by the system.

4b
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2 marks

Draw a Sankey diagram to represent the energy transferred by the turbine in the hydroelectric dam, indicating clearly the scale used.

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5a
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2 marks
A holiday park is deliberating whether to install photovoltaic cells or solar heating panels on the roofs of their chalets. 

Distinguish between a solar heating panel and a photovoltaic cell using considerations of the energy transfers involved.

5b
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4 marks

The holiday resort wishes to heat a 125-litre water tank from 10 °C to 40 °C over 2 hours to provide hot water for the chalet every 24 hours. The maximum amount of solar radiation incident upon the roof at any one time is 8.53 × 10−4 W mm−2.

Water has a density of 1.1 × 10kg m3 and a specific heat capacity of 4200 J kg °C−1.

One photovoltaic cell is a rectangle of dimensions 500 mm and 300 mm. The power output of one cell is 215.36 W when radiation is at its maximum intensity.

The solar heating panel is 67% efficient. 

Compare the area on the roof required by the solar heating panels and the photovoltaic panels.

5c
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2 marks

Justify the difference between the values calculated in part (b). 

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