P2.4 Current Electricity Flashcards
What is a fuse?
A safety measure designed to melt and breaks the circuit
What is a voltmeter?
It is used to measure potential difference (voltage).
What is an ammeter used for?
It is used to measure electrical current.
What does a fixed resistor do?
It limits the current in a circuit.
What does a diode do?
It allows the current to flow in one direction.
What does a switch do?
It allows the circuit to be closed and opened to allow flow.
What does a heater do in a circuit?
It transfers electrical energy into heat energy and emits it.
What does a variable resistor do?
It limits the current but can be changed.
What does an indicator (bulb) do?
It is a light source and shows the flow of electricity.
What does a light emitting diode (LED) do?
It emits light when current passes through it.
What is the equation for time, current and charge flow?
Current(amps) = charge flow (coulombs) /time taken(seconds)
What is the equation for voltage, current and resistance?
Voltage = current x resistance
The ….. is always the same anywhere in a series circuit.
Current
….. is shared across all components in a circuit.
Voltage
The total ….. of the circuit is the separate resistors added together.
Resistance
The total ….. through the whole circuit is the sum of the currents in each ‘loop’ of the circuit.
Current
The ….. across each component is the same.
Potential difference (voltage)
….. that are different will change the current flowing through it.
Resistors
Explain how a Van der Graff works.
The belt in the Van der Graff rubs against a felt pad.
The belt becomes positively charged because electrons are ‘scraped off’.
The belt carries that charge onto the metal dome.
The dome becomes charged.
The charge transfers to you and your hair becomes positively charged.
Your hair separates because the positive charges repeal each other.
When a polythene rod is rubbed with a dry cloth, how and where are electrons transferred?
Electrons from the cloth transfer onto the atoms in the rod, which makes the rod become negatively charged and the cloth become positively charged.
When a perspex rod is rubbed with a dry cloth, how and where are electrons transferred?
Electrons from the rod are transferred onto atoms in the cloth, which makes the rod become positively charged and the cloth become negatively charged.
What is resistance?
The force opposing electron flow in a circuit created by ions in the wires
What is potential difference?
The difference in energy between one point and the next
Explain why resistance will increase with heat.
Thermal energy will transfer into kinetic energy. Therefore, the ions gain more energy to bump into the electrons.
