electricity and magnetism

physics chapter 1

what is static electricity?

when electrons are transferred when two insulators are rubbed together, giving the object magnetic charges

what do like and opposite charges do?

like charges repel and opposite charges attract

what is an electric field?

the field charged objects have around them and the lines show how the positive charge will act.

how are the components connected in a series circuit?

the components are in one loop and the current is the same everywhere

how is the potential difference worked out in a series circuit?

the pd in each component added up is the same as the pd across the whole battery.

what is a parallel circuit?

a circuit that contains multiple branches, allowing for current to split and flow across each component independently.

how is the current worked out in a parallel circuit?

the currents in the branches add up to create the total current in the circuit.

how is the potential difference worked out in a parallel circuit?

the pd across each component is the same as the pd across the whole battery

what is the resistance?

a measure of how easy it is to pass through a component

what is a conductor?

a material that allows electric charges to pass through easily and has low resistance

what is an insulator?

a material that doesn’t allow electrical charges to pass through easily and has high resistance.

how well can a material conduct?

depends on the number of free electrons.

what is ohm’s law?

r = v/i

what does r, v and i stand for in ohm’s law?

r is resistance, v is pd and i is current

what is the unit of resistance?

ohm

what is the unit of current?

amps (A)

what is the unit of pd?

volts (V)

what are the poles of a magnet called?

north and south

how can you see the field lines of a magnet?

by using a small compass or iron fillings

what does it mean if the field lines are closer?

the magnetic field is stronger

what pole is at the top of the planet in earth’s magnetic field?

south pole

what is a current?

the amount of current flowing per second

what is a current measured with?

ammeter (connected in series)

when are electromagnets magnetic?

when they have a flow of current, so it can be turned off

how are electromagnets created?

by running a current through a coil of wire

what makes an electromagnet strong?

the iron core in the middle of the coil

how can you make an electromagnet stronger?

by adding more turns of wire on the coil or using more current

what are one of the uses of electromagnets?

making motors or speakers

how do levitating trains travel more faster?

there is no friction

how do motors work?

applying a current to the coil of wire making it electromagnetic

what causes the motor to drive?

the force between the coil of wire and the permanent magnet nearby