Conservation of energy
What Conservation of energy means in Physics A-Level, as defined for AQA, OCR.
Definitions of Conservation of energy
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Reference: AQA
Each charge carrier that completes the circuit transfers energy from the source to the components, and the sum of potential differences around any closed loop equals the source emf.
Links the stores so that the elastic potential energy of the spring equals the kinetic and gravitational potential energy of the launched mass.
The principle that energy is conserved per unit charge, which is why around any closed loop the sum of e.m.f.s equals the sum of p.d.s.
The total energy in a closed system stays constant; energy is transferred between stores but never created or destroyed.
The first law is a statement of this applied to a system, linking internal energy change to heating and work.
In every transfer, the total energy is conserved: the total energy before equals the total energy after.
Topics that use Conservation of energy
- Bulk properties of solids (AQA A-Level)
- Circuits (AQA A-Level)
- Thermal energy transfer (A-level only) (AQA A-Level)
- Series and parallel circuits (OCR A-Level)
- Work and conservation of energy (OCR A-Level)
Related terms
- Conservation of charge
- Breaking stress
- Brittle versus ductile force–extension graphs
- Change of state
- Circuit analysis
- Conservation of energy in electrical circuits
- Conservation of energy in mechanical systems
- Density
Using Conservation of energy in the exam
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