Static Electricity (11) Flashcards
How can an insulator be charged by friction?
When certain insulating materials are rubbed together, electrons are scraped off of one material and dumped onto the other. They are not free to move as the material is an insulator.
How do objects become charged?
The materials become electrostatically charged with the one which loses electrons becoming positive and the one gaining electrons becoming negative.
What are common electrostatic phenomena?
Shocks:
As static electricity builds up on objects (friction - electrons being picked up), it increases the potential difference between objects until electrons jump from one object to another causing a shock.
Lightning:
Static electricity builds up in clouds due to friction in between water and ice particles. When the charge is large enough it creates a large potential difference and the electrons travel through the air to neutral or oppositely charged objects.
Induction:
Rubbing a balloon against hair or clothes causes it to be electrostatically charged. When you put it up against a wall, the charges on the surface move a little repelling like charges and leaving opposite charges on the wall attracting the balloon to it.
What does earthing do?
Connects a charged object to the ground via a conductor giving electrons an easy route to travel to the ground and prevent a charge build up.
How are electrostatic charges used in sprayers?
The droplets are charged using electrodes. The droplets all contain the same charge so they repel each other once they come out of the nozzle. The object is given the opposite charge and the droplets are attracted to the object giving it an even coat and minimising waste.
Why is static electricity dangerous?
When refueling vehicles, static electricity can build up in the tank which can cause a spark to ignite the fuel. Also static electricity can interfere with communications on planes.
What is an electric field?
The region where an electric charge experiences a force.
How can the concept of an electric field explain static electricity?
When an object becomes statically charged, it creates its own electric field. This causes electrons to be attracted or repelled from the object. A high potential difference creates a strong electric field. This causes electrons to be removed and travel through air causing sparks and lightning.
