Questions and Answers
What is a disadvantage of renewable energy sources compared to non-renewable sources?
What is a significant environmental impact of fossil fuel extraction?
Why has the development of renewable energy become increasingly important?
Which of the following is a primary use of energy?
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What technological development has been essential for the increased suitability of renewable energy?
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What is the unit of power?
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Which method is NOT effective in reducing energy waste?
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Which of the following describes efficiency?
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How does thermal conductivity affect heat transfer?
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Which of the following is a renewable energy source?
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What happens to energy in all system changes?
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What characteristic of a motor makes it more powerful?
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Which of the following processes is a way to increase the efficiency of a system?
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What happens to kinetic energy when a moving vehicle slows down?
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Which formula represents the calculation of gravitational potential energy?
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What is the unit of measurement for power?
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What defines a system in terms of energy storage?
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Which of the following is true about specific heat capacity?
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In the calculation $E_k = \frac{1}{2}mv^2$, what does 'm' represent?
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When a spring is stretched, what type of energy is stored in it?
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What does the gravitational field strength value of 9.8 $m/s^2$ represent?
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Study Notes
Energy Stores
- A system refers to an object or a group of objects where energy storage changes during system alterations.
- When a ball rolls and strikes a wall, kinetic energy converts into sound energy.
- Vehicles converting kinetic energy to thermal energy while slowing down due to friction between brakes and wheels.
Calculating Energy
- Kinetic Energy Formula: ( E_k = \frac{1}{2} mv^2 )
- m: mass (kg), v: speed (m/s), ( E_k ): kinetic energy (J).
- Elastic Potential Energy Formula: ( E_e = \frac{1}{2} ke^2 )
- ( E_e ): elastic potential energy (J), k: spring constant (N/m), e: extension (m).
- Gravitational Potential Energy Formula: ( E_p = mgh )
- ( E_p ): gravitational potential energy (J), g: gravitational field strength (9.8 m/s²), h: height (m).
- Specific Heat Capacity: energy = mass × specific heat capacity × temperature change.
- ( \Delta E = mc\Delta T )
- ( \Delta E ): change in thermal energy (J), m: mass (kg), c: specific heat capacity (J/kg°C), ( \Delta T ): temperature change (°C).
Power
- Power measures the rate of energy transfer or work done: ( P = \frac{E}{t} ) or ( P = \frac{W}{t} )
- P: power (W), E: energy transferred (J), t: time (s), W: work done (J).
- A motor's power is determined by how quickly it can perform work, demonstrating faster energy transfer.
Energy Transfers
- Energy can be transferred, stored, or dissipated but not created or destroyed, leading to energy deemed ‘wasted’.
- Reducing waste involves:
- Lubrication (e.g., oil in motors) to limit friction losses.
- Thermal insulation (e.g., double glazing) to conserve thermal energy.
Thermal Conductivity
- Higher thermal conductivity allows heat to transfer efficiently, impacting energy transfer rates.
- Thick, low thermal conductivity walls reduce cooling rates; thin metal sheets lose heat quickly.
Efficiency
- Efficiency quantifies useful work relative to total energy input:
- ( \text{efficiency} = \frac{\text{useful energy output}}{\text{total energy input}} )
- Enhancing efficiency involves reducing waste and recycling output energy.
Energy Resources
Main Energy Sources
- Non-renewable: fossil fuels (coal, oil, gas) and nuclear fuel.
- Renewable: biofuels, wind, hydroelectricity, geothermal, tidal, solar, and water waves.
Renewable vs. Non-Renewable
- Renewable sources replenish naturally; non-renewable provide high energy output but are finite.
- Renewable energy's significance is rising with finite fossil fuels; reliability can vary (e.g., solar and wind).
Main Energy Uses
- Key applications: transport, electricity generation, and heating.
Environmental Impact
- Energy extraction affects landscapes (e.g., fossil fuels) and can create visual pollution (e.g., wind turbines).
- Fossil fuels release harmful emissions; renewable sources like solar and wind produce electricity without emissions.
Patterns and Trends in Energy Use
- The Industrial Revolution marked fossil fuels as a principal energy source due to ease of mining and high energy output.
- Recent technology advancements have improved the usability of renewable energy sources.
- Balancing increasing energy demands with environmental considerations is complex and influenced by political, social, ethical, and economic factors.
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Description
Explore the key concepts of energy stores in this AQA GCSE Physics quiz focused on Topic 1. Understand how energy changes within different systems, such as a rolling ball and a slowing vehicle. Perfect for those studying for their higher tier physics exams.
