Electricity Flashcards
What is electrostatics?
The study of charges at rest.
What are examples of static electricity?
Lightening
Spray painting
Photocopies
Van der Graf generator
According to what theory does electric current move from the positive terminal to the negative terminal.
Conventional theory
How does a battery become ‘flat’?
As the cell is used, the original chemicals change and are used up, while new substances are formed. When all the chemicals have reacted, the cell no longer supplies electrical energy
What is the energy transformation in a cell?
Chemical to electrical
What is current?
Current is the rate of flow of charge around a circuit
What is current measured in
Amperes
How are ammeters connected and why?
Ammeters are connected in series and have low resistance in order to not altar the current of a circuit to a great extent.
What are the 3 factors that must be meant in order for current to flow?
A circuit must be closed in order for current to flow
There must an electrical energy source
There must be resistance
Draw the symbols of the following: Cell Battery Conductor Open switch Closed switch Resistor Voltmeter Light bulb Ammeter
in book
What is charge?
The amount of electrons that are moving in the circuit?
What is a coulomb?
The amount of charge that passes a point per second in a circuit when the current is 1 ampere.
What is the elemental charge?
One electron minus is equal to 1, 6×10 to the -19 C
How is current in a series vs parallel?
Current in a series circuit is the same throughout, whereas current is split/shared in a parallel circuit
What happens when resistors are added In series vs parallel?
In series as resistance increases current decreases (resistance is inversely proportional to current)
In parallel; as restores are added, overall resistance in the circuit decreases and therefore current increases.
What is potential difference?
Potential difference is the difference in electrical potential energy per unit charge between to points in a circuit.
Why are voltmeters always connected in parallel?
Voltmeters have high resistance, therefore would stop or slow current in series.
Required to measure potential difference across two points (either side of the resistor) in the circuit
What happens to voltage in a parallel vs series circuit?
Voltage is shared between resistors in series.
Voltage is not shared between resistors in parallel.
What relationship does voltage have to resistance?
Voltage is directly proportional to resistance. If the amount of resistance of a resistor goes up, the amount of voltage drawn from the battery will also increase
What is resistance?
A materials opposition to the flow of electric energy
What are the 2 factors that affect the resistance in a circuit?
The resistance of the conductor
The resistance of the resistors in the circuit
What is the relationship between resistance and current?
They are inversely proportional. As resistance increases, the amount of current decreases.
What is the relationship between resistance and voltage?
They are directly proportional. As resistance increases, voltage increases
Tabulate the differences between current, voltage and restrictions in a series vs parallel.
In book
What is ohms law?
The current flowing through a conductor is directly proportional to the voltage across the conductor provided the resistance remains constant.
What are the factors that effect ohms law?
Length of the conductor: longer the conductor the more resistance to the flow of current
Thickness(diameter):the thicker the conductor, the less resistance to flow of current
Temperature: the hotter the conductor, the less
What happens to total resistance in parallel vs series?
In series the total resistance increases
In parallel the total resistance decreases
