Show:
Electricity I
Electricity II
Magnetism I
Magnetism II
100
Why are parallel circuits better suited for your home?
One light can go out without causing the other lights to go out
100
What is the law of charges?
Like charges repel and opposite charges attract
100
What is the law of magnets?
Opposite poles attract, like poles repel
100
How is the earth like a magnet?
It has a south pole (geographic north pole) and a north pole (geographic south pole)
200
What is Ohm's law and what are the different units?
V (potential difference--volts) = I (current—amperes) x R (resistance – ohms)
200
What is the difference between direct and alternating current?
In direct current electricity flows in the same direction (i.e. batteries) and in alternating current the electrons flow in different directions (i.e. generators and your home)
200
What is a generator?
A device that changes mechanical energy to electricity
200
What is an electric motor?
A device that converts electrical energy to mechanical energy
300
What are the three ways of building static electicity?
Friction – when two objects rub together and electrons move from the surface of one object to surface of another Induction – when charges on an object are rearranged without physical contact Conduction – electrons are transferred from one material to another by direct contact
300
What is resistance?
The force caused by internal fricton that slows or opposes the movement of electrons through a material.
300
What are domains?
Groups of atoms aligned with magnetic poles
300
What is a compass?
An instrument with a freely turning magnetized needle that can be used to determine direction
400
What is an electric current and what is it dependant on?
Region around a charged object in which other charged objects experience an electric force. Dependant on the amount of charge.
400
What is potential difference?
The difference in potential energy between any two places in a circuit. Compares how much energy electrons have in a circuit between any two points.
400
What is electromagnetic induction?
The generatopm of current by moving a magnet through a wire coil
400
What are the characteristics of electromagnets?
Strength of the magnetic field increases with the number of turns and with the current strength
500
Why does it lightning?
A cloud forms and the top of the cloud is positive and the bottom of the cloud is negative. As the cloud’s electric field grows, the earth becomes positively charged and the electrons travel from the negative cloud to the positive earth.
500
What is Electric Power and how is it calculated?
The rate at which electrical energy is converted to another from of energy P (Electrical Power) = I (Current) x V (Voltage difference)
500
What is the difference between a permanent magnet and a temporary magnet?
In a permanent magnet the domains are always lined up in the same direction and in a temporary magnet the domains are only lined up when a strong magnet is nearby.
500
What is a Magnetic Field and what are its characteristics?
It is the invisible area around a magnet where a magnet can exert a force. Strongest at the poles and weakest in the middle