Electricity and magnetism Flashcards
What happens when a positive charge is with a positive charge?
They repel.
What happens when a positive charge is with a negative charge?
They attract.
What are the three parts to an atom and what are their charges?
1) proton (+1)
2) electron (-1)
3) neutron (0)
Overall what is the charge of an atom?
Neutral.
What is current?
The flow of electrical charge (electrons) around a complete circuit per a second.
What is current measured in and what with?
Measured amps using an ammeters.
What is a cell?
A chemical store of energy, which provide the push that moves charge around a circuit.
What is a battery?
Two or more electrical cells joined together.
What are motors?
A component or machine that spins when a current flows through it.
What is potential difference?
A measure of the push of a cell or battery / the energy the cell or battery can supply.
What two things can potential difference tell you?
1) The potential difference across a cell tells you about the size of the force on the charges.
2) How much energy can be transferred to the components in the circuit by the charges.
What is used to measure potential difference and what is the measurement?
A voltmeter measures potential difference and it is measured in volts.
What is rating?
The value of potential difference at which a cell or bulb operates.
What are the 2 types of circuit?
Parallel and series.
What are the differences between the 2 types of circuit?
In series, all the components are in one big loop but in parallel the components are in a separate loop. This means that in series circuits if one component breaks none of the circuit will work as the current can not flow.
What are the differences in current between the 2 types of circuit?
In a series circuit, the current is the same everywhere but when more components are added, the current decreases. In a parallel circuit, the current in each branch is always the same and adds up to the total current.
What are the differences in potential difference between the 2 types of circuit?
The potential difference of each component adds up to the potential difference of the cell/battery in a series circuit. In a parallel circuit, each component has the same potential difference (including the cell/battery).
Complete the equation:
Current (A)=
Potential difference (V)
__________________
Resistance (Ω)
What is resistance?
How difficult it is for current to flow through a component in a circuit.
What is resistance measured in?
Ohms (Ω)
Complete the equation:
Resistance (Ω) =
Potential difference (V)
__________________
Current (A)
A magnet has a ……………………. and a …………………….
north pole
south pole
Give 4 examples of magnetic materials.
Iron
Steel
Cobalt
Nickel
What is a magnetic field?
A region where there is a force on a magnet or magnetic material.
In magnetic field lines, which way do the arrows always go?
They always go from North to South.
What is an electromagnet?
A temporary magnet produced by an electric current.
What does the strength of an electromagnet depend on?
- Number of coils
- Amount of current flowing through
- Type of core
What are the differences between a permanent magnet and an electromagnet?
An electromagnet can be turned on or off. Electromagnets can be made a lot stronger than permanent magnets. Electromagnets are run by electricity.
What is a relay?
Electrical devise that uses current through it in one circuit to switch on and off a current in a second circuit.
