P5: Electric Circuits Flashcards
What causes the build up of static electricity?
It is caused by friction, when two insulating materials are rubbed together.
Which particles move when static builds up?
Electrons are scraped off one and put onto the other
Describe the forces between objects with like charges
Two thinsg with the same elctric charge will repel each other
Describe the forces between objects with opposite charges
Opposite charges attract
Explain how static electricity can make synthetic clothers crackle when you take them off
When synthethic clothes are dragged over each other (like in a tumble drier) or over your head when taking them off, electrons get scraped off, leaving static charges on both parts - they then attract, stick together and cling to you the little sparks/shocks crackle as the charges rearrange themselve
Explain why metals are good conductors of electricity
Metals are good ocnductors of electricity because they are full of electrons that are free to move. They are delocalised
Explain what current, voltage and resistance are in a circuit
Current is the flow, voltage is the driving force that pushes the current round and resistance is cause by components that resist the flow of charge.
What happens to the amount of current in a circuit if voltage of the battery is increased
The current also increases, move current will flow
What is another name for voltage? What is it a measure of?
Potential difference is the measure of how much energy is transferred to or from each unit of charge as it moves between two points.
What is Ohms Law?
Resistance= voltage/Current
Explain in terms of energy why PD is shared out in a series circuit
The PD is shared in a series circuit between components. This is because the total work done on the charge by the battery must equal the total work done by the charge on the components.
What happens to voltage when cells are added to a series circuit?
If you connect several cells in series, you get a bigger total voltage because each charge in the circuit passes though all the cells get a ‘push/ from each cell in turn. Voltages add up
What voltage is UK mains electricity supplied at? Why is AC used?
230V, AC is used for mains electricty because it is easier to generate than DC, and is easier and simpler to distribute over long distances.
DEFINE: Electromagnetic Induction
Is the creation of volatge by moving a magnetic in or near a coil of wire
What are the four factors that affect the size of a induced voltage?
Strength of magnetic field
Speed of rotation
Number of turns in the core
Whether it has a iron core inside the coil
