What does Ohm’s law state?
The current through a conductor is proportional to the potential difference across it, provided the temperature remains constant
Where are ammeters placed in a circuit?
In series with other components
Where are voltmeters placed in a circuit?
In parallel with the part of the circuit that they are measuring
What does a straight line graph passing through the origin indicate in a practical verification of Ohm’s law?
Current and voltage are directly proportional
What is the equation that links potential difference (V), current (I), and resistance (R)?
V = I × R
What are the units for potential difference, current, and resistance?
Potential difference: volts (V), current: amps (A), resistance: Ohms (Ω)
What happens to the resistance of a filament bulb as the potential difference increases?
The resistance increases as the filament becomes hotter
At what voltage does a diode start to allow current through?
About 0.6V
What is power measured in?
Watts (W)
What are the two equations you need to know for power?
- P = V × I
- P = E/t
What is the suitable fuse rating for an appliance that operates at 2A?
A fuse rating higher than 2A, but suitable for the appliance’s operation
What is the function of a fuse in an electrical appliance?
To protect the appliance from overheating and potential fire hazards
What happens to a fuse wire when the current becomes too high?
The wire becomes hot and melts, breaking the circuit
What is the equation to calculate the cost of using an electrical appliance?
Cost = Power (kW) × Time (h) × Cost per kWh
Fill in the blank: Electrical energy is supplied to homes via the ______.
national grid
What is a common domestic appliance fuse rating?
- 3A
- 5A
- 10A
- 13A
- 30A
What should you do to find the correct fuse for an appliance?
Find the current the appliance takes using the formula P = V × I
What is the suitable fuse rating for a fridge-freezer with a power rating of 400W at 230V?
3A fuse
What is the energy usage measurement used by electricity companies?
Kilowatt-hours (kWh)
