electricity Flashcards
Describe static electricity
The force between two charged objects
How can some insulators become charged?
Rubbing them together
What is charge?
Transfer of electrons.
Gain electrons = negative charge
Loss of electrons = positive charge
Charges ______, opposite charges ________.
Charges repel, opposite charges attract.
When do static shocks occur?
When there is potential difference between the charged object and the earth.
What does each circuit have and what does it show?
Its own symbol to show the components in a circuit.
Describe a battery
Two or more cells put together
Describe current
The rate of flow of charge and is measured in amps
Current (I) =
charge (Q) ÷ time (t)
Potential difference (V) =
energy transferred (E) ÷ charge (Q)
Describe current and voltage in series circuits
Current is the same, voltage is shared
Describe resistance in a series circuits
Resistance adds up
Describe current and voltage in a parallel circuit
Shared between the branches. The sum of all branches is the total current/voltage.
What does adding more resistors do in parallel circuits?
Decreases the total
resistance.
Resistance is measured in _______
Ohms (Ω)
What does a higher resistance cause?
Lower current, higher temperature
Total resistance in a series circuit
Adds up
Total resistance in a parallel circuit
It decreases
Resistance (Ω) =
Potential difference (V) ÷ current (Amps)
In a wire the as the current ______ so does the ________. Resistance is ________
In a wire the as the current increases so does the voltage. Resistance is proportional
In a filament bulb what does resistance do if the temperature increases?
Increases
Describe the forward resistance and backward resistance in a diode?
The forward resistance is low the backward resistance is high
What happens to a thermistors resistance if its temperature increases?
It decreases
What happens to a LDR’s resistance if the light intensity on it increases?
It decreases
