Topic 11 - Static Electricity Flashcards
What can happen when insulating materials are rubbed together?
They can become (statically) electrically charged
Why can insulators become electrically charged when rubbed together?
Electrons transfer from one material onto the other
What charge does the material gaining electrons become?
Negatively charged
What charge does the material losing electrons become?
Positively charged
What would happen when 2 electrically charged objects are brought close together?
They exert a force on each other
What happens when 2 identically charged objects are brought close together?
They exert a repulsive force on each other and repel
What happens when 2 oppositely charged objects are brought close together?
They exert an attractive force on each other and attract
What is a non contact force
The repulsive or attractive force acting between 2 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.
Electrons flow to/from earth to balance the charge.
This can 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 lightening occur?
Clouds build up an electrostatic charge
When this becomes large enough the clouds discharge via the air to the earth
Why does a charged balloon stick to the wall?
When a positively charged balloon is placed next to a wall, the + charges near the balloon get repelled to other parts of the wall.
Leaving an area of the wall with a negative charge, attracting the + charged balloon towards the wall.
How does earthing remove excess charge?
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 friction between pipes and fuel
When charge builds up a spark may be discharged
Spark could start fire if reacts w flammable fuel
This is resolved by earthing the vehicle and pump
What is an electric field?
Region where an electric charge will experience a non contact force
What direction do the field lines in an electric field point?
In the direction that a + charge would move
