Electricity (Seneca) Flashcards
Components are shown using …
symbols
Straight lines show wires joining the …
components
The wires don’t pass through the …
components
An electric current is the …
flow (movement) of electric charges.
Electric current is measured in …
amperes (A).
The flow of charge (C) =
current (A) x time (s).
The flow of charge (1.) = current (2) x time (3.).
- C
- A
- s
A current has the ———— at every point in a single closed loop.
same value
A current has the same value at …
every point in a single closed loop.
What is needed for a current to flow?
- closed circuit
- source of potential difference
- electrons
What are Amperes (A) the unit for?
Electrical current
The current is equal to the …
charge divided by the time.
I =
Q/t
The movement of electric charges is the basis of …
electrical current
An electrical conductor is a …
material that allows electric currents (flow of electric charges) to pass through it.
All ——- are electrical conductors.
metals
An electrical insulator is a …
material that doesn’t allow electric currents (flow of electric charges) to pass through it.
—————— are electrical insulators.
Plastic and glass
An electrical conductor has lots of …
charges that are free to move.
In a metal, the charges that are …
free to move are electrons.
The electric current through the metal is the flow of …
these free electrons.
An electrical insulator has …
no free electrons.
An electrical insulator has no free electrons. No charges are …
free to move and carry a current.
Which charges are free to move in metals?
Electrons
Give examples of electrical insulators.
- wood
- plastic
- rubber
Potential difference (p.d.) is measured in —– and is also called voltage.
volts (V)
Potential difference (p.d.) is measured in volts (V) and is also called …
voltage
The energy is transferred to the electrical components in a circuit when …
the charge carriers pass through them.
We use a ——- to measure potential difference (or voltage).
voltmeter
We use a voltmeter to measure …
potential difference (or voltage).
Potential difference is the …
difference in the amount of energy that charge carriers have between two points in a circuit.
potential difference(V) =
current (A) ×resistance (Ω)
A potential difference of one Volt is equal to …
one Joule of energy being used by one Coulomb of charge when it flows between two points in a circuit.
voltage (V) ×charge (C) =
energy(J)
An ammeter measures the …
flow of current that passes through it.
Ammeters have to be connected in …
series (in the same loop of the circuit) with the electrical component whose current you are measuring.
Voltmeters measure the…
potential difference (voltage) between two points in a circuit.
Voltmeters must always be connected in …
parallel (on a separate branch of the circuit) with the two points being measured.
The current is a 1. . Current is measured through 2. .
- flow of charge
- a component
Potential difference is the energy used between two points in a circuit, therefore it is measured …
between two points either side of a component.
Potential difference is the energy used between two points in a circuit, therefore it is measured between two points either side of a component.
We describe this as …
the potential difference measured across a component.
When charge flows in an electric circuit, the size of the current is affected by two things:
- The resistance: If the resistance is increased, the current will decrease.
- The potential difference: If the potential difference is increased the current will increase.
Resistance is measured in …
ohms, Ω.
Resistance is a measure of the…
difficulty of the flow of current through a component
An electric current will increase when the number of ohms …
decreases
An electric current will increase when potential different…
increases
An electric current will increase when resistance…
decreases
resistance (Ω) =
voltage (V) / Current (A)
We calculate potential difference using a voltmeter and current using an ammeter at the …
same time
The longer the wire, the ————- the resistance.
higher
We can plot a current-voltage graph by …
varying the potential difference across a circuit component.
what is Ohm’s Law?
current = potential difference/resistance.
In Current-Voltage Graph for a Resistor, the slope of the graph is equal to …
1/resistance.
In Current-Voltage Graph for a Resistor, the constant slope (straight line graph) tells us that the resistance is …
constant.
In Current-Voltage Graph for a Resistor, what effect will increasing the current through a filament bulb have on the graph?
It will curve because the temperature and resistance is rising.
In Current-Voltage Graph for a Filament Lamp, The gradient (slope) ———– at larger potential differences.
decreases
In Current-Voltage Graph for a Filament Lamp, when the current through a filament (thin wire) lamp increases, the temperature of the lamp …
increases.
In Current-Voltage Graph for a Filament Lamp, when the current through a filament (thin wire) lamp increases, the temperature of the lamp increases.
This increases …
the resistance of the lamp and causes the graph to curve.
We can plot a current-voltage graph by changing the potential difference across a circuit component and measuring the current. A constant slope tells us that the resistance is …
constant.
A diode is a …
component that only allows current to flow through it in one direction.
A rectifier is a …
component that turns an alternating current (repeatedly changes direction) into a direct current (one direction)
Diodes act as rectifiers as they …
block the alternating current when it changes direction.
A thermistor is a …
component where resistance changes with its temperature.
A thermistor is a component where resistance changes with its temperature.
Usually, increasing temperature ——— the resistance.
decreases
We can use a thermistor to …
turn a heater off when a house reaches certain temperatures.
A light dependent resistor (LDR)s resistance changes with …
light intensity
A light dependent resistor (LDR)s resistance changes with light intensity.
Usually, increasing light intensity ———— the resistance.
decreases
We can use LDRs to …
switch lights on when it gets dark or to know whether or not a camera phone needs to use “flash”.
A diode is a component through which current can flow in only one direction. Because of this, diodes act as …
rectifiers.
The diode blocks the …
alternating current when it changes direction.
The flow of current transfers …
energy from the energy source to the components.
The components then transfer energy to …
their surroundings.