P2 - Electricity Flashcards
What is electric current?
A flow of electrical charge.
Current flows in a complete (closed) circuit only if there is a potential difference.
What is the unit of current?
Ampere, A.
What drives the flow of electric charge in a circuit?
Potential difference (or voltage).
Its unit is the volt, V.
What is the relationship between current and resistance?
The current depends on the potential difference and the resistance of the component.
What happens to the current when resistance increases?
The current decreases for a given potential difference.
How is the total charge through a circuit calculated?
Q = It, where Q is charge, I is current, and t is time.
What is the formula to calculate charge flow?
Q = It.
If a battery charger passes a current of 2.0 A over 2.5 hours, how much charge is transferred?
18,000 C.
What is the symbol for a battery in a circuit diagram?
Battery symbol.
What does a switch symbol represent in a circuit diagram?
An open or closed switch.
What is the symbol for a filament lamp in a circuit diagram?
Filament lamp symbol.
What does the fuse symbol indicate in a circuit diagram?
A fuse.
What does LED stand for in circuit diagrams?
Light Emitting Diode.
What is the symbol for a resistor in a circuit diagram?
Resistor symbol.
What is a variable resistor used for?
To adjust resistance in a circuit.
What is the purpose of a voltmeter in a circuit?
To measure potential difference (voltage).
What does a diode do?
Allows current to flow in one direction only.
Fill in the blank: The unit of resistance is _______.
Ohm, Ω.
What is an LDR?
Light Dependent Resistor.
What is the function of a thermistor?
To change resistance with temperature.
What does an ammeter measure?
Current in a circuit.
What does the formula V = IR represent?
The relationship between potential difference (V), current (I), and resistance (R)
This formula is fundamental in understanding electrical circuits.
What is the formula to calculate current (I) from potential difference (V) and resistance (R)?
I = V ÷ R
This rearrangement of V = IR allows for calculating current when V and R are known.