Electricity(p) Flashcards
What are the components required in a basic circuit?
Battery, cells, filament lamp, switch and wire
What is the current?
the measure of electrons around a circuit recorded in amps
What is potential difference?
force driving flow of electrons recorded in voltage
What is the resistance?
Everything that resists/opposed flow of electrons
What is the “conventional current” suggest about the flow of electrons?
Current flows through positive to negative
What will happen when there is an increase in temperature for the wires?
There will be an increase in resistance due to the metal vibrating faster, making it harder for electrons to pass through wire
What do diodes do?
Only allow current to flow one way around a circuit
What is the equation which included voltage, current and resistance?
V=IR
Voltage =current x resistance
(This increases proportionally)
what are the Components in a circuit?
-cell
-battery
-open switch
-closed switch
-filament lamp
-fuses
-diode
-light emitting diode
-fixed resistor
-variable resistor
-light dependant resistor
-thermistor
What are light dependent resistors?
When there is a high resistance when it’s dark
What are thermistor?
High resistance means more cold
What is the formula involving voltage, energy, current and time?
Energy = voltage x current x time
How is energy prepared to be sent access national grids?( stgs)
- Nuclear power station generates thermal energy. Which is used to turn water into steam.
- Steam then rises and turns turbines. Which provides kinetic energy
- The kinetic energy is converted to electrical energy m. That’s sent actos national grid
What does the national grid do?
Transmits huge amounts of power to towns
Explain the process of the national Grid?
•energy goes through step up transformer, which increases voltage and decreases current( to minimise power loss)
• then transmitted between pylons.
• step down transformers reduce voltage for towns and increase current
What happens if the current or voltage is too high?
Is dangerous for voltage
If current to high. Then the energy is wasted by heat when transmitting current
When does electricity demand peek?
In afternoon
How many volts and hertz does a main supply have?
-230 volts
-50hz
What 3 wires are in a plug?
Live wire
Earth wire
Neutral wire
What is the live wire?
-brown
-carries potential difference
-carries 230v
-carries electricity into plug
What is neutral plug?
-blue
-completes circuits by carrying away current
-carries 0v
-carries electricity out of plug
What is earth wire?
-doesn’t normally carry current
-yellow and green
-carries 0v
-stops appliance casing becoming live
-provides alternating path to flow to prevent electric shock
What are wires made from?
Copper and coated in layers of insulating plastic
What are the risks of electrical appliances?
• surges(when person turns appliance on an off. Fault in circuit/ appliance)
• damaged appliance
• fires
• electric shock
What are the method of precaution for surges?
Fuses
Circuit breakers
Earthing
Double insulate
What are fuses (in appliance)
Breaks circuit when current is too high. Is very thin piece of wire. When heated melts and breaks circuit. {So no current can flow in}
-fuse rating always a bit above appliance
-simple and cheap
-permanently broken after single usage
What are circuit breakers?
-breaks circuit whenever there’s a surge
-by tripping the circuit breaker. To turn of circuit so it’s reset.
-more expensive than fuse
What is earthing (using earth wire)?
When Earth wire provides alternative pathway. Where electricity is diverted through the earth wire.
As the earth wire is also connected to the appliance
What is double insulate?
-doesn’t conduct electricity
-can’t get electric shock
-only has live and neutral wire
-covered in plastic casing
-exposes no metal parts
