Test-Electricity and Circuits Flashcards
What happens when two insulating materials are rubbed against each other?
They become electrically charged by friction. Electrons move from one to another. One is negatively charged and the other is equally positively charged.
Why do you need to rub an object to make it attract another object?
It makes the object charged. Charged objects attract neutral objects.
What happens when more bulbs are added to a parallel circuit?
Nothing. The bulbs stay the same brightness.
Do two negative charges repel or attract?
Repel
What type of circuit is used for home lighting?
A parallel circuit.
What do you call an object what no total charge?
Neutral
What do electrons carry in a circuit?
They carry energy from a cell to other components.
What is the symbol for resistance called, and what does it look like?
Ω. It is called Ohms
What is an electric current?
A flow of charged particles called electrons.
Does a longer wire have more or less resistance than a shorter one?
More
What is the formula for power?
Power=volts x current.
What can a short circuit do to wires?
Make them overheat.
I’m a series circuit us one bulb breaks, what happens to the rest of the circuit and why?
The bulbs go out. This is because the electrons can’t get through the bulb and give power to the next one.
Equation for resistance?
Potential difference divided by current.
What charge are electrons?
Negative
What is the resistance of a bulb if it has a current of 10 A flowing through it when a potential difference of 240 Volts is out across it?
24 Ohms
What provides yeh potential difference in a circuit?
The cell
What has a higher resistance, insulators or conductors?
Insulators
If a material has a current if 0.00025 A and 2.4 resistance, is it like let to be an insulator or conductor?
Insulator
If a material has a potential difference if 2.4 and a current of 0.15, is it likely to be an insulator or a conductor?
Conductior
What does a battery rating tell you?
The potential difference the battery will supply.
What is the equation for a moment?
Moment = force x distance
Name the advantages and disadvantages of low energy bulbs.
They are low energy consuming, but expensive and not very bright.
What direction does the north seeking pole point towards when free to rotate?
The north (Scotland)
What is the region around a magnet when it has magnetic effect called?
The magnetic field
Name four magnetic materials
Iron steel cobalt and nickel
Do like poles repel or attract?
Repel
If I put two opposite poles next to eachother, what would happen?
They would attract
What is a magnetic field?
A region of space where magnetic materials experience forces
Name uses of magnets.
They are used in Compasses, fridges, speakers, microphones and computers
Do magnetic field lines ever cross?
No
The closer the lines are what happens to the magnetic dield?
They field is stronger
What is the only way you can test if something is magnetic?
See if they repulse from another magnet.
What is a permanent magnet?
A magnet that retains its magnetism
What is a temporary magnet?
They loose their magnetism when the magnetic field disappears. Otherwise they act like a permanent magnet.
What happens to the magnetism of an electromagnet as you add coils of wire?
The magnetism increases.
How can you strengthen an electro magnet?
Increase the voltage, increase the number of coils or insert an iron core.
What does passing a current through a wire do?
It creates a magnetic field around the wire.
