Energy Stores in Physics

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Questions and Answers

What is the formula for calculating power?

Power = work done × time

Power = energy × time

Power = total energy input ÷ useful energy output

Power = work done ÷ time (correct)

Which unit is used to measure work done?

Joules (J) (correct)

Seconds (s)

Watts (W)

Kilowatts (kW)

How is efficiency measured?

Efficiency = useful energy output ÷ total energy input (correct)

Efficiency = useful power ÷ useful energy output

Efficiency = useful power ÷ total energy input

Efficiency = total work done ÷ time

What is one method to reduce unwanted energy transfers in machines?

Applying lubrication Signup and view all the answers

What does insulation do in buildings?

Reduces energy transfers Signup and view all the answers

What does the law of conservation of energy state?

Energy cannot be created or destroyed Signup and view all the answers

What is the relationship between efficiency and wasted energy?

Higher efficiency indicates less wasted energy Signup and view all the answers

Which of the following is a characteristic of renewable energy resources?

They can be naturally replenished Signup and view all the answers

What is one disadvantage of hydroelectric power?

It blocks rivers, stopping fish migration. Signup and view all the answers

Which type of energy transfer occurs when a charge moves through a distance?

Electrical transfer Signup and view all the answers

What is a notable feature of wind energy?

It has no CO2 emissions when generating electricity. Signup and view all the answers

What type of energy storage involves magnets that are attracting or repelling?

Magnetic store Signup and view all the answers

Which statement is true about mechanical energy transfer?

It requires a force to move an object through a distance. Signup and view all the answers

What is a potential environmental impact of nuclear fission?

It may damage ecosystems. Signup and view all the answers

How is energy from electrostatics transferred?

Through the movement of charged particles. Signup and view all the answers

Which option accurately reflects the reliability of solar energy?

It is intermittent and can depend on weather conditions. Signup and view all the answers

What is the formula for calculating kinetic energy?

Kinetic energy = 0.5 x mass x velocity^2 Signup and view all the answers

What does gravitational potential energy depend on?

Mass, gravitational field strength, and height Signup and view all the answers

Which of the following is NOT a characteristic of tidal energy?

It is a reliable source of electricity. Signup and view all the answers

What is the unit of power in the context of energy transfer?

Watt (W) Signup and view all the answers

Which energy source is characterized as renewable but unreliable due to calm seas?

Waves energy Signup and view all the answers

What is a potential environmental issue associated with geothermal energy?

It may release greenhouse gases such as CO2. Signup and view all the answers

What information does the equation for gravitational potential energy provide?

It relates mass, height, and gravitational strength. Signup and view all the answers

Which energy source produces no CO2 while generating electricity?

Waves energy Signup and view all the answers

What is one advantage of fossil fuels in electricity generation?

Reliable and can generate electricity constantly Signup and view all the answers

Which statement is true about wind energy?

It generates electricity without producing CO2 Signup and view all the answers

What is a disadvantage of hydroelectric energy?

It can negatively impact fish migration Signup and view all the answers

Which of the following describes a disadvantage of geothermal energy?

Fluids drawn from the ground may contain greenhouse gases Signup and view all the answers

How does nuclear energy generate electricity?

By splitting atoms in a process called fission Signup and view all the answers

What is a key characteristic of renewable energy sources?

They can be replenished naturally Signup and view all the answers

What is one reason why wind energy might be considered unreliable?

It relies on wind availability Signup and view all the answers

Which advantage is associated with renewable energy sources such as solar and wind?

They produce sustainable electricity with low emissions Signup and view all the answers

What type of energy resource is produced from the nuclei of atoms?

Nuclear Fuel Signup and view all the answers

Which energy resource is considered renewable?

Bio Fuel Signup and view all the answers

What is a major disadvantage of fossil fuels?

Produces carbon dioxide Signup and view all the answers

Which energy storage method involves energy stored in raised objects?

Gravitational Potential Store Signup and view all the answers

Which option describes the reliability of nuclear energy?

Reliable electricity generation Signup and view all the answers

What is a major environmental concern with nuclear energy?

Producing radioactive waste Signup and view all the answers

What is a distinct advantage of using biofuels?

Carbon neutral Signup and view all the answers

Which form of energy is stored in moving objects?

Kinetic Store Signup and view all the answers

Study Notes

Energy Stores

Chemical store: Energy is stored in the bonds of molecules. When these bonds break, energy is released, e.g., burning fuel.
Kinetic store: Energy is stored in objects that are moving. The faster the object moves, the more kinetic energy it has.
Gravitational Potential store: Energy is stored in objects that are raised against gravity. The higher the object is, the more gravitational potential energy it has.
Elastic Potential store: Energy is stored in a stretched or compressed object, e.g., a spring.
Internal store: Energy is stored within the particles of a substance. It is a combination of kinetic energy (particle movement) and potential energy (particle separation). Heating or cooling modify this store.
Nuclear store: Energy is stored in the nucleus of an atom due to the strong forces holding the protons and neutrons together. This energy can be released through nuclear fission (splitting the atom) and nuclear fusion (combining atoms).
Magnetic store: Energy is stored in magnets due to the magnetic forces of attraction or repulsion between them.
Electrostatic store: Energy is stored when electric charges attract or repel each other.
Mechanical store: Transfer of energy occurs when a force moves an object through a distance.

Methods of Energy Transfer

Electrical transfer: Energy is transferred when an electric charge moves through a circuit.
Radiation transfer: Energy is transferred by electromagnetic waves, e.g., light, heat, and radio waves.
Heat transfer: Energy is transferred when an object is heated by conduction, convection, or radiation.

Equations

Kinetic Energy: Ek = 0.5mv², where Ek is kinetic energy (J), m is mass (kg), and v is velocity (m/s).
Gravitational Potential Energy: Ep = mgh, where Ep is gravitational potential energy (J), m is mass (kg), g is the gravitational field strength (N/kg), and h is height (m).
Power: P = E/t, where P is power (W), E is energy transferred (J), and t is time (s).
Power: P = W/t, where P is power (W), W is work done (J), and t is time (s).
Efficiency: Efficiency = Useful Energy output/Total Energy Input
Efficiency: Efficiency = Useful Power output/Total Power Input

Energy Resources

Fossil fuels: Non-renewable resources that provide electricity and heat. Examples include coal, oil, and natural gas.
- Advantages: Reliable, relatively cheap, abundant.
- Disadvantages: Produce carbon dioxide (a greenhouse gas), sulphur dioxide (acid rain), and air pollution.
Nuclear Fuel: Non-Renewable resource providing electricity.
- Advantages: Produces no carbon dioxide during generation, reliable.
- Disadvantages: Creates radioactive waste that requires long-term storage, expensive to build and decommission power stations.
Wind: Renewable resource providing electricity.
- Advantages: No CO2 produced, clean, renewable.
- Disadvantages: Unreliable, high construction cost, noise pollution and visual impact.
Hydroelectric: Renewable resource providing electricity, can also be used for irrigation.
- Advantages: No CO2 produced, reliable source.
- Disadvantages: Blocks rivers impacting fish migration, can be unreliable during droughts.
Geothermal: Renewable resource providing electricity and heat.
- Advantages: Does not damage ecosystems, reliable source of clean energy.
- Disadvantages: Fluids from the ground may contain greenhouse gases like CO2 and methane, which contribute to global warming.
Tidal: Renewable resource providing electricity.
- Advantages: No CO2 produced, clean, renewable.
- Disadvantages: Unreliable due to tidal variations, can damage tidal ecosystems like mudflats.
Waves: Renewable resource providing electricity.
- Advantages: No CO2 produced, clean.
- Disadvantages: Unreliable, can't produce electricity during calm seas.
Solar: Renewable resource providing electricity and heating.
- Advantages: No CO2 produced, clean, renewable.
- Disadvantages: Unreliable, does not produce electricity at night, limited production on cloudy days, expensive to construct.
Biofuel: Renewable resource used for heating and transport.
- Advantages: Carbon neutral (releases as much CO2 as it absorbs while growing).
- Disadvantages: Currently expensive to produce.

Key Terms

Dissipation: Energy becoming spread out, "wasted" energy, usually converted to heat.
Lubrication: Reducing energy transfer through friction by applying a lubricant (e.g., oil) to surfaces.
Insulation: Reducing energy transfer by using insulators (non-conductive materials), e.g., in buildings.
Conservation of Energy: Energy cannot be created or destroyed, but it can be transferred and transformed from one form to another.

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Explore various types of energy stores in physics including chemical, kinetic, gravitational potential, elastic potential, internal, and nuclear energy storage. This quiz will test your understanding of how energy is stored and transformed in different systems.