Electricity and Electromagnetism Flashcards
What is an Electric Current?
The flow of charge around a circuit
What does The Potential Difference do?
It pushes the Current around
What happens if you increase the potential difference
More current will flow
Do all batteries have the same potential Difference?
No
What is Resistance
It is how easily Electricity Can Flow
What components can have Resistance in a Circuit?
Resistance is anything in a circuit that slows down the flow of current
What is Resistance measured in
Ohms
How can you find out the Resistance?
By doing
Resistance =
Potential Difference divide by current
Batteries provide the driving force to push charge around a circuit
What is this driving force called?
Potential Difference
What is the only way of telling if an object is charged?
to see if it repels another charged object.
What does it mean by “in series”?
Connected to a circuit in such a way that the same current flows through each component in turn.
When two components are connected in series,______________________
you can follow the path through both components without lifting your finger or going back over the path you have already taken.
How can you find out if an object is a conductor or an insulator?
You set up a series circuit with a cell, lamp and wires. Leave a gap in the circuit between two of the wires. Then connect the two wires using pieces of each material and see if the lamp lights up
Examples of Conductors
Metal Elements
Graphite
Mixtures of metals
Salt Solution
Liquid Calcium Chloride
Examples of Insulators
Most Non mental elements
Diamond
Plastic
Wood
Rock
What 3 things do you need to know when drawing magnetic field diagrams?
each field line has an arrowhead on it
the field lines come out of the north pole and go into the south pole
the field lines are more concentrated at the poles
What is an Electromagnet?
An electromagnet is a type of magnet in which the magnetic field is produced by an electric current
How can Electromagnet be turned off?
Unlike Bar magnets, Electromagnets can reverse the direction of current (turn the battery around)
What is the DC Effect?
When you put a length of wire in a magnetic field and pass a DC current through it (such as from a battery), the wire will move.
To make a simple DC motor, you need:
two bar magnets
a coil of wire wrapped around something to support it
an axle for the coil of wire to spin around
two half rings (‘split rings’)
How does coil rotation happen?
the coil of wire has an electrical current running through it because it is connected to the cell this generates a magnetic field around the wire the current
is turned on and off at the correct time so the magnetic field of the wire interacts with that of the two magnets this makes the coil rotate
How does A DC motor work?
The two bar magnets are held so that the north pole of one magnet faces the south pole of the other magnet.
The coil of wire is mounted in the gap between the two magnets. The split rings make electrical contact with the coil and reverse the current every half turn.
When an electric current flows through the coil, a force is exerted on the coil, causing it to spin.
Dp
Electrons move from the Duster to the polythene rod
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Electrons move from the Acetate rod to the Duster
What is a magnetic field?
A region where magnetic materials experience a force
How can u find the magnetic field lines using iron fillings
The iron fillings will align along the field lines
What is the only way of telling if an object is charged? Justify your answer
To see if it repels another charged object as a charged object can attract uncharged insulators eg pieces of paper
