Topic 11 - Static Electricity Flashcards
What can happen when insulating materials are rubbed together?
They become statically electrically charged
Why can insulators become electrically charged when rubbed together?
Electrons transfer from one material to the other
Material gaining electrons becomes negatively charged
Material losing electrons becomes equally positively charged
What happens when two identically charged objects are brought close together?
They repel
What happens when two oppositely charged objects are brought close together?
They are attracted to each other
Give an example of a non-contact force
The repulsive or attractive force acting between two electrically charged objects
Why do we feel an electric shock?
When an object builds up an electrostatic charge, it needs to be ‘earthed’ via a conductor
Electron flow to/from the earth to balance the charge
This can also occur if you touch a charged object whilst you are earthed
If earthing occurs through a person/animal, it causes an electric shock
Why does lightning occur?
Clouds can build up an electrostatic charge
When this charge becomes large enough the clouds discharge via the air to the earth
This is known as lightning
Why does a charged balloon stick to the wall?
When a positively charged balloon is placed next to a wall, the positive charged get repelled to other parts of the wall. This leaves an area of negatively charged wall which attracts the positively charged balloon towards the wall, making the balloon stick
How does earthing remove excess charge?
It provides a path with a low resistance for the electrons to flow either from the device or towards the device to reduce the charge build up
How does static electricity cause danger when fuelling cars?
Static charge can build up due to the friction between the pipes and the fuel
When the charge builds up, a spark may be discharged
The spark could start a fire if it reacts with the flammable fuel
How is the danger of static electricity when fuelling cars dealt with?
Earthing the vehicle and purp
What is an electric field?
A region where an electric charge will experience a non-contact force
What direction do the lines in an electric field point?
In the direction that a positive charge would move
In a parallel field, what does the lines being closer together indicate?
A stronger field
How can you use electric fields to explain static electricity?
The object that is statically charged will generate an electric field
This field attracts the electrons on other objects causing a flow of charge resulting in sparks
