CIE A Level Physics复习笔记9.3.1 Resistivity
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?transfer?some, or a...
CIE A Level Physics复习笔记9.2.4 Resistance in a Filament Lamp
Resistance in a Filament Lamp The?I-V?graph for a filament lamp shows the current increasing at a proportionally slower rate than the potential difference I-V characteristics for a filament lamp Th...
CIE A Level Physics复习笔记9.2.3 I-V Characteristics
I–V Characteristics As the potential difference (voltage) across a component is increased, the current also increases (by Ohm’s law) The precise relationship between voltage and current is differen...
CIE A Level Physics复习笔记9.2.2 Ohm's Law
Ohm's Law Ohm’s law states that for a conductor at a constant temperature, the?current?through it is?proportional?to the?potential difference?across it Constant temperature implies constant resista...
CIE A Level Physics复习笔记9.2.1 Resistance
Defining Resistance Resistance is defined as the?opposition?to current For a given potential difference:?The higher the resistance the lower the current Wires are often made from copper because cop...
CIE A Level Physics复习笔记9.1.4 Electrical Power
Calculating Electrical Power In “Work, Energy and Power”, Power?P?was defined as the?rate of doing work Potential difference is the?work done per unit charge Current is the?rate of flow of charge S...
CIE A Level Physics复习笔记9.1.3 Potential Difference
Defining Potential Difference A cell makes one end of the circuit positive and the other negative. This sets up a?potential difference?(d) across the circuit The potential difference across a compo...
CIE A Level Physics复习笔记9.1.2 Electric Current: Calculations
Calculating Electric Charge Current can also be defined as the charge passing through a circuit per unit time Electric charge is measured in units of?coulombs (C) Charge, current and time are relat...
CIE A Level Physics复习笔记9.1.1 Electric Current
Defining Electric Current Electric current is?the flow of charge?carriers and is measured in units of?amperes (A)?or?amps Charge can be either positive or negative When two oppositely charged condu...
