Electricity Flashcards
What is electric current?
The movement of charge (electrons) through a closed conducting circuit.
What is required for electric current to flow through a circuit? (2)
A closed switch (no break in circuit)
A cell or sourse of energy
What is charge?
Electric charge are the electrons flowing through the circuit.
What is the symbol for charge?
Q
What is current strength?
The rate at which electrons flow through a circuit: fast or slow.
What is the symbol for current?
I
What is the unit of measurement of current?
Amperes (A)
How does a cell store chemical substances?
As chemical potential energy.
What is the stored energy in a cell called?
Potential different or voltage.
What happens when a cell is connected to an external circuit?
These chemical substances react to produce electrical charge with a high potential energy.
What is the energy transfer carried out by the cell?
Chemical potential energy ➡️ Electrical potential energy
What happens as the charge leaves the positive terminal of the cell and enters the wires?
It has a high kinetic energy.
What happens when charge reaches a resistor?
The use/expand a lot of their energy and the electrons return to the negative terminal of the cell.
What happens once electrons have returned to the cell?
They are recharged with high potential energy so that they can re-enter the circuit.
What is a battery?
More than one cell connected together in series.
What does an increase in cells in series result in?
Increase strength of current. Increase potential different across cells.
What happens when adding cells in parallel?
Potential difference and current stays the same.
What happens when adding resistors in parallel?
Decrease in total resistance which therefor increases the current.
What happens when adding resistors in series?
There’s an increase in total resistance and decrease in total current.
What happens to the total current in series?
It remains the same throughout?
What happens to the total current in parallel?
It splits amongst the different branches.
What do the resistors do in series?
Divide total voltage.
What happens to the current and potential difference in parallel?
The current splits, but the potential difference is the same throughout.
What is resistance?
The opposition to the flow of current.
What is the symbol for resistance?
R
What is the unit of resistance?
Ohm
What is a conductor?
Substances that allow charge to flow through them.
What are resistors?
Conducting materials chosen to control current or to provide useful energy transfer.
What are the four factors that impact resistance?
Material of conductor.
Thickness of conductor.
Length of conductor.
Temperature of conductor.
Which thickness of wire has more resistance?
Thinner wires offer more resistance than thicker wires.
What length of conductor offers more resistance?
Longer wires offer more resistance than shorter wires.
What temperature of the conductor has a higher resistance?
Hotter conductors have higher resistance than colder conductors.
