Static And Current Electricity Flashcards
What is in the nucleus of an atom
Protons
Mass 1
Charge +1
Neutrons
Mass 1
Charge 0
How does static happen
When two insulating materials are rubbed together electrons are scraped off one and moved to the other
This leaves a positive static charge on one and a negative static charge on the other
Only the electrons can move not the protons
What happens when a polythene rod is rubbed with a duster
The electrons move from the duster to the rod giving the rod a negative charge and the duster a positive charge
What happens when an acetate rod is rubbed with a duster
Electrons move from the rod onto the duster so the duster has a negative charge and the rod has a positive charge
What are the rules of charges
Opposites attract
Same charges repel
The further away the weaker the force
How does static effect clothing
When synthetic clothes are dragged over each other like in a tube dryer electrons get scraped off leaving static charges on both objects
The charges snap back to the original charges causing a spark
How does static charge effect cars
It can build up between clothes and the car seat so when you get out of the car and touch the metal door the charge flows and shocks you
Some cars have conducting strips that earths the charge
What causes static
Friction of two objects running past each other
How does static effect door handles
If you walk on a nylon carpet wearing insulating shoes the electrons will transfer from the floor onto the person when you touch a door handle the charge flows and shocks you
Why do Ballons stick to walls
Rubbing a ballon against your hair or clothes causes electrons to be transferred to the ballon giving it a negative charge
When you hold it up to a wall the charges on the surface of the wall can move a little so the negative charge on the wall is repelled so a positive charge is left on the surface which attracts the ballon
This is called induction
How does a charged comb pick up small pieces of paper
Running a comb through your hair transferred electrons to the comb then because its negatively charged it can pick up small pieces of paper by repelling the negative charge
What is lightning
Rain drops and ice bump together in the clouds knocking off electrons which leaves the bottom of the cloud negative and the top positive this creates a huge voltage and a big spark
How are electrostatic charges used in paint sprayers
The spray gun is charged which charges the small drops of pain each drop repels the others so you get a fine spray with an even coat
The object is given the opposite charge to the gun which attracts the pain there is little waste and no paint shadows
How does electrostatic charge effect fuelling
As fuel flows out of the fuel pipe a static can build up this can create a spark which could cause an explosion in a dusty or fumey place
How are objects earthed
Connecting a charged object to the ground using a conductor
This provides an easy way for the charges to get to the ground so no charge will build up and spark
Electrons flow down the conductor to the ground if the charge is negative and electrons to flow up the conductor to the object if the charge is positive
Fuel tankers must be earthed to avoid explosions
