Electricity Flashcards
Chapter 13 revision
What is electric current
The rate at which electric charge flows
What is the flow of electrons in a circuit
Negative terminal to Positive terminal
What is the definition of Potential difference
a measure of energy, per unit of charge transferred between two points in a component.
SI unit of current and the device to measure it
Ampere: (A) and Ammeter
Arrangement of an Ammeter
Series. Positive terminal to Positive terminal of the cell and Negative terminal to Negative terminal of the cell.
What does a Ammeter measure
Current flowing through the circuit
SI unit of Potential Difference and the device to measure it
Voltage: V and a Voltmeter
How to connect a voltmeter
Connect in parallel to the component. Negative terminal to the Negative terminal of the cell and Positive terminal to the Positive terminal of the cell.
What is the definition of electrical resistance
measure of how much of a component opposes the flow of electrical current
When the slider is to the left what happens
The rheostat has minimum resistance. The current then increases.
When the slider is to the right what happens
The rheostat has more resistance. The current in the circuit then decreases.
Why is it better to arrange fixed resistors in parallel
This way there is more than one path for current to flow. This reduces the overall resistance in the circuit. Increasing current output.
What are the types positive effects of electricity
Chemical, Heating, Magnetic
What is electroplating
When electric current passes through chemical solutions and liquids
What is Electroplating used for
Used for extracting metals or coating a thin layer of metals.
What is the heating effect?
When electric current passes through a heating element and some electrical energy is converted to heat energy
What is the magnetic effects of electricity
Electric current flows through a magnetic material it will gain magnetism and become an electromagnet. It can also deflect compasses
Two Hazards of electricty
Electric fires and Electric shocks.
Why do insulators not conduct electrity?
The electrons cannot flow freely.
Electic fire causes
Overloading, excess current flow, melting of wires and damage to the circuit
How do Electric shocks occur
- Insulating materials of a wire is worn out
- Exposure of live wires
- Water exposure
- Inserting our fingers or objects that can conduct electricity into sockets.
Safety devices
fuse and circuit breaker
Fuse function
A component with a low resistance wire. When the fuse blows it causes and open circuit when the circuit has too much current flowing through it.
Circuit breaker function
It has many switches connected to each household appliance. When the current flow is too large or the circuit is faulty, the switch linked to it trips and cuts off the current.
What is power
Electrical energy converted per unit of time.
Watt to KiloWatt formula
(Watts x time in hours) divided by 1000
Si unit of power
Watt: (W)
