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...
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...
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...
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...
A-Level 商務（Business Management）和A-Level 經濟（Economy）都是商科方向的課程。于是有很多學生會在選課階段對著兩門課程糾結不已，不知道究竟該選擇哪門課程。事實上，雖然A-Level 商務（Business Manageme...
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 ...
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...
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...
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 ...
