Edexcel A Level Physics:复习笔记4.1 Density
Density Density is the mass per unit volume of an object Objects made from low-density materials typically have a lower mass For example, a balloon is less dense than a small bar of lead des...
Edexcel A Level Physics:复习笔记3.20 Resistance & Illumination
Modelling the Variation of Resistance with Illumination Light can cause a change in conductivity of some semi-conductors When light is absorbed by the material it causes more electrons to be availa...
Edexcel A Level Physics:复习笔记3.19 Resistance & Temperature
Modelling the Variation of Resistance with Temperature 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 thei...
Edexcel A Level Physics:复习笔记3.18 Core Practical 3: Investigating E.M.F. & Internal Resistance
Core Practical 3: Investigating E.M.F. & Internal Resistance Aims of the Experiment The overall aim of the experiment is to investigate the relationship between e.m.f. and internal resistance b...
Edexcel A Level Physics:复习笔记3.17 E.M.F. vs. Terminal Potential Difference
E.M.F. vs. Terminal Potential Difference Terminal Potential Difference The terminal potential difference (p.d.) is the potential difference across the terminals of a cell If there was no internal r...
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...
