What is charge?
Charge is a property of some particles, that causes them to experience a force when placed into an electric field.
What is current?
Current is the rate of flow of charge.
What is conventional current?
Conventional current goes from positive to negative.
How is electron flow different to conventional current?
Electron flow goes from negative to positive.
What is direct current?
Direct current only moves in one direction.
What is the elementary charge?
The charge of an electron is known as the elementary charge, e, with a value of approximately 1.6 x 10^-19 Coulombs.
What is the relative charge of protons and electrons?
Protons have a relative charge of +1, and electrons have a relative charge of -1.
What is potential difference?
Potential difference, or voltage, is the energy per unit charge that a current transfers around a circuit.
What is resistance?
Resistance is opposition to electrical current, measured in Ohms (Ω).
What does Ohm’s law state?
Current is directly proportional to voltage (at constant temperature)
What happens to resistance in a filament lamp as it heats up?
As the filament heats up, thermal agitation between particles increases resistance.
What is the function of a diode in a circuit?
Diodes behave like one-way valves in a circuit, allowing current to flow in only one direction.
What are thermistors and light-dependent resistors (LDRs)?
Thermistors and LDRs act like variable resistors, whose resistance decreases as either the ambient temperature or light intensity increases.
What is power?
Power is the rate of transfer of energy, measured in Watts (W).
What is the equation for power in a circuit?
Power (P) = Current (I) x Voltage (V).
How can work done by a circuit be calculated?
Work done (W) = Current (I) x Voltage (V) x time (s)
What is an electron-volt?
An electron-volt (eV) is the amount of kinetic energy gained by an electron that’s experienced an accelerating potential of one volt.
What happens to current if voltage is increased?
As the potential difference increases, the current also increases (Ohm’s law).
Units of charge?
Coulombs
Units of current?
Amps
Units of work/energy?
Joules
Units of potential difference?
Volts
Units of power?
Watts
Units of resistance?
Ohms
