Edexcel A Level Physics:复习笔记3.3 Ohm's Law
Defining Resistance Resistance Resistance is defined as the opposition to current It is further defined by Ohm's Law, which says that the resistance of a conductor is given by the ratio of p...
Edexcel A Level Physics:复习笔记3.2 Potential Difference
Potential Difference Potential Difference A cell makes one end of the circuit positive and the other negative This sets up a potential difference across the circuit This is sometimes known as the v...
Edexcel A Level Physics:复习笔记3.1 Electric Current
Electric Current Electric Current Electric current is defined as: The rate of flow of charge It is measured in units of amperes (A) or amps The charge, current and time are related by the equation:...
Edexcel A Level Physics:复习笔记2.22 Efficiency
Efficiency The efficiency of a system is a measure of how well energy is transferred in a system Efficiency is defined as: The ratio of the useful power or energy transfer output from a syst...
Edexcel A Level Physics:复习笔记2.21 Power
Power The power of a mechanical process is the rate at which energy is transferred Since work done is equal to the energy transferred, power can also be defined as the rate of doing work or the wor...
Edexcel A Level Physics:复习笔记2.20 The Principle of Conservation of Energy
The Principle of Conservation of Energy The principle of conservation of energy is a law of Physics which always applies to a closed system To apply conservation of energy, heat losses are usually ...
Edexcel A Level Physics:复习笔记2.19 Gravitational Potential Energy
Gravitational Potential Energy Gravitational potential energy (usually written Ep, but sometimes GPE) is energy stored in a mass due to its position in a gravitational field If a mass is lif...
Edexcel A Level Physics:复习笔记2.18 Kinetic Energy
Kinetic Energy Kinetic energy (usually written Ek and sometimes KE) is the energy an object has due to its motion (or velocity) The faster an object moves, the greater its kinetic energy &nb...
Edexcel A Level Physics:复习笔记2.17 Work
Work Work is defined as The amount of energy transferred when an external force causes an object to move over a certain distance If the force is parallel to the direction of the object's dis...
