Edexcel IGCSE Biology: Double Science 復(fù)習(xí)筆記 1.1.3 Living Organisms: Excretion Excretion Chemical reactions?that take place inside living cells are described as?metabolic reactions ...
Edexcel IGCSE Biology: Double Science 復(fù)習(xí)筆記 1.1.2 Living Organisms: Nutrition & Respiration Nutrition Organisms must obtain food to provide?energy Energy is necessary to carry out life proce...
Resistance in a Light-Dependent Resistor A light-dependent resistor (LDR) is a non-ohmic conductor and sensory resistor Its resistance automatically changes depending on the light energy falling on...
Edexcel IGCSE Biology: Double Science 復(fù)習(xí)筆記 1.1.1 The Unifying Characteristics of Living Organisms The Unifying Characteristics of Living Organisms In order for something to be considered...
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...
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...
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...
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...
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...
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...
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...
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...
