NS-Physics
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62 Terms
rheostat definition
an electrical circuit component that has the ability to change its resistance
How does the length of the resistor influence its amount of resistance
The longer the resistor the higher the resistance of the circuit
How does the thickness influence the amount of resistance
The thicker the conductor the more space for the current to flow through and therefore the lower its resistance
How does temperature influence the amount of resistance
When heating wires or resistors, the particles gain kinetic energy. The movement makes it more difficult for charges that are released from a battery to get through the wire. Therefore increasing the resistance
Conductor definition
A component made of material that allows electric current to flow through it
diode definition
an electrical circuit component that controls the flow of current in a particular direction
full term for LED
light emitting diode
what do LEDs do
convert electrical energy into light energy
Function of Light sensitive diodes
convert light energy into electrical energy
full term for LDRs
light dependent resistors
What are LDRs used for
automatically switch on/off lights as it gets lighter/darker
factors that affect resistance
Type of material
Length
Thickness
Temperature
semi conductor definition
substance that conducts electric current under certain conditions
Conductor definition
Component made of material that allows electric current to flow through it
insulator definition
Substance that doesn’t allow electric current to flow through it
Cell definition
device that produces electricity by converting chemical energy into electrical energy
electrodes definition
a solid substance through which an electric current enters or leaves a cell
electrolytes definition
the medium for the movement of ions within cells
Battery definition
more than one cell connected together
Voltage definition
measure of the amount of potential energy stored in a cell or used by a circuit component
voltmeter definition
an instrument used to measure voltage
what is voltage measured in
volts (V)
The higher the voltage of a cell therefore means..
the more energy each electron has available to spend while it moves through the circuit
what happens when cells are connected in series
the voltage of the battery inscreases
what happens when cells are connected in parallel
the voltage of a parallel battery is the same as the voltage of each cell
resistance definition
the ability of a component in an electrical circuit to oppose the flow of current
resistor definition
A component that opposes the flow of current in an electrical current
What is the voltage of cells connected in series equal to
the sum of each individual cell
What is a series circuit
electric circuit where electrical components are connected one after the other and provides only one pathway for the current to flow through
What is the total voltage across all the resistors in a series circuit equal to
the voltage over the battery
What is the total voltage in a series circuit equal to
The sum of the voltages across all the resistors in the circuit
Current definition
flow of electric charge through an electrical conductor
ammeter definition
instrument used to measure the strength of electric current in an electrical current
what happens when the amount of resistors in a series circuit increases
the total current decreases
parallel circuit definition
electric circuit where electrical components are connected next to each other and provides more than one pathway for the current to flow through
For resistors connected in parallel, what is the voltage measured across each of the resistors equal to
the voltage of the battery
what happens to the current in a parallel circuit
it splits
In a parallel circuit, what is the total current provided by the battery equal to
the sum of the currents through all the resistors
What is the input of cells
Chemical energy stored in materials that the cell is made of
What is the process of cells
Chemical reaction takes place inside the cell and allows electrons to flow
Output of cells
Electron flow makes electricity flow possible in the external circuit
What happens to the current in a circuit when more resistors are connected in parallel
the current increases
What is ohms law
voltage is equal to current multiplied by resistance
In a parallel circuit, what is the reading across all the cells the same as
one cell
Where will the biggest current flow
in the resistor with the least resistance
What are resistors in series referred to as
potential dividers
What happens to the current when it is branched
it divides
in a parallel circuit, what is the sum of the current in each branch equal to
the current in the main circuit
what are parallel resistors referred to as
current dividers
advantages of light bulbs connected in series
one switch allows all the light bulbs to shine
disadvantages of light bulbs connected in series
If one bulb goes out/doesn’t work properly, all the light bulbs will go out
The more light bulbs connected in series, the dimmer each one glows
The relation between light bulbs connected in parallel with the amount of current and total resistance
The more light bulbs connected in parallel, the smaller the total resistance in the circuit, the larger the current that flows
advantages of light bulbs connected in parallel
It’s possible to switch on all the light bulbs with one switch
possible to switch on each light bulb separately
Disadvantages of light bulbs connected in parallel
the more light bulbs connected, the bigger the current needed from the battery therefore the battery will not last long
Overload definition
Excess electrical current in a circuit
Fuse definition
A safety device in a circuit that melts and breaks if the current exceeds safe levels
Earth leakage definition
A safety device used to protect people from electric shock by redirecting the current into the ground
Circuit breaker definition
A safety device that will open the circuit if too much current flows in the circuit
A problem relating to parallel connections
It’s easy to overload the circuit (excess currents) with too many branches (each requiring a current of their own)
What can overloading a parallel circuit lead to
Overheating
Fires
Short circuits
How does a circuit breaker work
A current enters the circuit through the live wire and flows through a coil of wire with a soft iron core inside. While doing so an electromagnet is formed, its strength is directly related to the amount of current flowing through the coil. If the current is too large, the electromagnet becomes strong enough to attract the side of the contacts closest to it, breaking the contact and stopping the flow of the current. On a circuit board in the house, a circuit board will trip and the switch will turn off
Formula for the cost of electricity
Cost is equal to power rating of appliance in kw multiplied by the number of hours multiplied by the unit cost of electricity