P5 P5; Electricity flash cards 0.0 / 5 ? PhysicsElectricityGCSEOCR Created by: jasmine_kasCreated on: 22-07-14 08:43 Why do two objects, when rubbed together, become charged? Because elctrons are transferred from one object to the other. 1 of 25 How do objects with similar charges (both negative or both positive) interact? They repel eachother. 2 of 25 How do objects with opposite charges (one positve and one negative) interact? They attract eachother. 3 of 25 What charge does an electron have? Negative: -1 4 of 25 What is electric current? The flow of charge. 5 of 25 What is electric current measured in? Amperes: Amps 6 of 25 Which parts in an electric circuit contain many charges which are free to move? The components (for example; a light bulb) and the metal conductors (wires). 7 of 25 When a circuit is made, what does the battery cause the charges to do? The battery cause the free charges to flow around the circuit in a continuos loop (they are not used up). 8 of 25 What is an electric current in metallic conductors? In metallic conductors an electric current is a movement of free electrons that are present in such materials. 9 of 25 In terms of free charges, what is the difference between insulators and conductors? Insulators have few free charges whereas conductors have many free charges. 10 of 25 How does voltage affect current? The larger the voltage of the battery in a given circuit, the bigger the current. 11 of 25 How do components effect current? Resistors, lamps motors and other components resist the flow of charge through them. 12 of 25 What is the relationship between resistance and current? The larger the resistance the smaller the current. 13 of 25 Why is the resistance of wires usually ignored? It is very small and therefore negligable. 14 of 25 What happens when electric charge flows through a component? Work is done by the power supply and energy is transferred from it to the component and/or the surroundings. 15 of 25 What is power (in watts; W)? Power is the measure of the rate at wich the electrical power supply transfers energy to a comonent or device and/or it's surroundings. 16 of 25 What is the equation for power? Power = Voltage x Current / W = V x A 17 of 25 Why do resistors get hotter when there is an electric current running through them? This heating effect is cause by collisions between the moving charges and the ions in the wire. 18 of 25 How does the heating of a lamp filament effect its appearance? It becomes hot enough to glow. (light energy) 19 of 25 Why do two or more resistors in series have more resitance than each one on its own? The battery has to move charges through both of them one after the other so the resistance is graeter. 20 of 25 Why do two resistors or more in parallel have less resistance than each one on its own? A parallel circuit provides more paths for charges to move along so the total resistance is less. 21 of 25 What is the equation for resistance? Resistance = Voltage/Current / Ohms = V/A 22 of 25 What does the voltage across a battery provide? It provides a measure of the ‘push’ of the battery on the charges in the circuit. 23 of 25 What is potential difference? Another term for voltage. 24 of 25 What happens when two or more components are connected in series to a battery? a) the current through each component is the same. 25 of 25
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