Topic 11: Static electricity Flashcards
What can happen when insulating materials rub together?
They can be (statically) electrically charged.
Why can insulators be electrically charged when rubbed together?
Electrons transfer from 1 material to another.
Material losing the electrons is positively charged.
The material gaining the electrons is negatively charged.
What happens when 2 electrically charged materials are brought close together?
They exert a force on eachother.
What happens when 2 identically charged objects get brought close together?
They exert a repulsive force on eachother and repel.
What happens when 2 oppositely charged objects get brought close together?
They exert an attractive force on eachother and attract.
Why do we feel and electric shock?
When an object builds up electric charge it needs to be earthed via conductor.
Electrons flow to/ from the earth to balance charge.
This also can happen when you touch a charged object whilst you are earthed.
If earthing occurs in an person/ animal it causes an electric shock.
Why does lightning occur?
Clouds build up an electrostatic charge.
When charge becomes large enough it’s discharged from clouds via air to earth.
This is known as lightning.
Why does charged balloon stick to wall.
When a balloon goes near a wall, the positive charges get repelled to another area on the wall, leaving an area with just negative charges which attracts positively charged balloon towards wall and sticks.
How does earthing remove excess charge
Provides path with low resistance which electrons flow either from or to device to reduce charge build up.
How does static electricity cause danger while fuelling cars.
Static charge can build up due to friction between pipes and fuel.
This could cause a spark, which may light fuel and cause fire.
This can be resolved by earthing fuel and pump.
How does static electricity cause danger while fuelling cars.
Static charge can build up due to friction between pipes and fuel.
This could cause a spark, which may light fuel and cause fire.
This can be resolved by earthing fuel 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 fields point.
Direction where a positive charge will move.
Describe the difference of electric field lines in a parallel field.
Straight lines, parallel to eachother, point from positive plate to negative plate and at edges lines are partially curved.
Which is stronger field?
IIIIIIIIIIIIII I I I I
———— ———–
Left as field lines closer together shows stronger field.
