Electricity Flashcards
What is an electrical conductor
An electrical conductor is a material that allows electrical charge to flow through it
What is an electrical insulator
An electrical insulator is a material that does not allow electrical charge to flow through it
What are the effects of charges objects
Like charges repel
Neutral charges are unaffected
Opposite charges attract
What happens when charge is tranfered
When the charge is transferred only electrons move
What happens to electrons with acetate and polythene
If acetate loses electrons, it becomes positive
If polythene gains electrons, it becomes negative
How does acetate become positively charged
When rubbed with the cloth the electrons move from the acetate to the cloth therefore leaving a negative charge on the cloth
How does polythene become negatively charged
When rubbed with the cloth the electrons move from the cloth to the polythene therefore leaving a positive charge on the cloth
how does the gold leaf electroscope become charged
A. the plate and the leaf are both neutrally charged
B. electrons are repelled down the leaf away from the negative rod
C. electrons leave the electroscope down the earthing wire
D. electroscope is left with positive charge when wire and rod have been removed
why does the balloon stick to the wall
balloon gains negative charge by gaining electrons from jumper (by friction)
negative charges on the wall are repelled away from balloon creating a positive charge near the balloon
opposites attract so the balloon is attracted to the wall
eventually balloon will fall off as it returns to a neutral charge
What is the electrical ball model
The van de graph generator
What happens between two charged generators is they receive too much charge and get too close
If to much charge builds up a spark could jump through the insulating air from the negative dome to a positive one
Where might the van de graph scenario happen in real life
In lightening when too much charge builds up an ddischarges into the ground
Where might the van de graph generator be dangerous
Large currents can kill a body or ignite a flammable liquid
Why do plane have rubber wheels
Rubber is an insulator
When the metal fuel pump is brought close to the aeroplane what could happen if too much static charge has built up on the plane
A spark out jump from the plane to the pump
Why could this be dangerous id the spark jumps
This could ignite the fuel and cause an explosion
How does the earthing wire connecting the pump to the plane keep the plane safe
Because the wire is a conductor
It allows all charge that has built up to flow off the plane down the wire to the earth to prevent the charge build up
Why does the paint achieve an even mist with no big droplets
Like charges repel so the paint repels away from itself creating an even mist
Why must the car be connected to the electrical supply to have a positive charge
Opposites attract so the paint which is negative is attracted to the car which is positive
What charge should the plates of a chimney have
Positive charge
Why
Opposites attact so the smoke wil be attracted to the walls and be removed from the air
What flows around a circuit
Electrons
What is their charge
Negative
What do they deliver
Energy
Where do they deliver it to
Components such as bulbs
Where do they get this from
Cells or batteries
For them to flow the circuit must be
Complete
What device controls the flow
A switch
What is current
Current is the rate at which the charge of electrons flow
What is current measured in
Amps
What is voltage
Voltage is the energy transfered
What is voltage also known as
Potential difference
What is voltage measured in
Volts
How do you define a series circuit
When the components are on s single loop
What are the advantages of series circuits
Simpler to construct
All components controlled with one switch
How would you describe a parallel circuit
Components are on multiple branches
What are the advantages of a parallel circuit
Switches on each branch control the components independently
What does the ammeter measure
Current
What does an ammeter measure by in units
Amps
What do voltmeters measure
Voltage
What do they measure volts in
Volts
What happens to current in a series circuit
It stays the same
What happens to current in parallel circuits
It splits at junctions
Why does it split at junctions
It takes that path with less resistance
What happens with voltage in series circuits
It is split to all the components
What happens to voltage in parallel circuits
On each branch the voltage is the same as the cell
What is ohms law
Voltage is directly proportional to current through a fixed resistance
What is the equation for voltage
V=IxR, voltage = current x resistance
What is the structure of an atom
Proton, neutron, electron(in shells)
