P4 Flashcards
What is a electrical charge?
Electrical charge is a fundamental property of matter
How much volts are in a normal electrical applaince?
230 - 240volts
What is voltage?
T
What is electrical current?
Electrical current is the flow of charge and it is measured in Amps (A)
Voltage is the same as…
Potential difference
What is potential difference?
Potential difference is a ‘difference’ between two points, this is important to remember when measuring it
The potential difference (voltage) between two points in a electric circuit is the work done ( energy transferred, J ) per coulumb of charge that passes between the points
What is elecrical resistance?
Electrical resistance or resistance in a circuit is the opposition to the flow of charge
What in a circuit could cause resistance?
The electrons flowing through a circuit have to push through lots of vibrating ions which resist the passage of electron flow
Explain the I-V graph for a filament bulb
The resistance of a bulb increases as the tempertaure of the metal filament increases. The ions in the metal vibrate more as the temperature increases. This resists the flow of electrons
Explain the I-V graph of a resistor
It follows Ohms law
The current flowing through a resistor at a constant temperature is directly proportional to the potential difference across it
Explain the I-V graph for a Diode
A diode only lets current flow in one direction
In the forward direction the line curves towards the current axis, the current is able to flow but isn’t directly proportional to potential difference.
In the backwards direction the resistance is very high so current cannot flow so the line is flat.
Explain the I-V graph for a thermistor
A thermistor is a component which changes resistance due to temperature
As the temperature increases a thermistors resistance decreases
Explain the I-V graph for an LDR
An LDR is a component which changes its resistance due to intensity of light.
As the light intensity increases an LDRs resistance decreases.
