Edexcel A Level Physics:复习笔记3.16 Internal Resistance
Internal Resistance All power supplies have some resistance between their terminals This is called internal resistance (r) Internal resistance causes some electrical energy to be transformed...
Edexcel A Level Physics:复习笔记3.15 Electromotive Force
Electromotive Force When charge passes through a power supply such as a battery, it gains electrical energy The electromotive force (e.m.f.) is defined as: The amount of chemical energy converted t...
Edexcel A Level Physics:复习笔记3.14 Potential Dividers & Variable Resistance
Potential Dividers & Variable Resistance The Potentiometer A potentiometer is a single component which can act as a potential divider. It consists of a coil of wire with a sliding contact A var...
Edexcel A Level Physics:复习笔记3.13 Potential Dividers
Potential Dividers The electrical voltages rule is defined as: The sum of the e.m.f.s in a closed circuit loop is equal to the sum of the potential differences around that loop Therefore, wh...
Edexcel A Level Physics:复习笔记3.12 Potential Difference & Conductor Length
Potential Difference & Conductor Length Potential Difference A cell makes one end of the circuit positive and the other negative. This sets up a potential difference across the circuit The pote...
Edexcel A Level Physics:复习笔记3.11 Current & Drift Velocity
Calculating Current & Drift Velocity Drift Velocity In a conductor, the current is due to the movement of charge carriers The charge carriers can be negative or positive However current ...
Edexcel A Level Physics:复习笔记3.10 Core Practical 2: Investigating Resistivity
Core Practical 2: Investigating Resistivity Aims of the Experiment The aim of the experiment is to determine the resistivity of a length of wire Variables Independent variable = Length, L, of the w...
Edexcel A Level Physics:复习笔记3.9 Electrical Resistivity
Electrical Resistivity All materials have some resistance to the flow of charge As free electrons move through a metal wire, they collide with ions which get in their way As a result, they t...
Edexcel A Level Physics:复习笔记3.8 Current-Potential Difference Graphs
Current-Potential Difference Graphs As the potential difference (voltage) across a component is increased, the current also increases (by Ohm’s law) The precise relationship between voltage ...
