P2.1+2 Flashcards
What causes static electricity
Build up of electrostatic charge in insulating materials
What causes electrostatic charge
When two insulators rub together, electrons are transferred from one to the other, as they are insulators, those electrons are trapped and some atoms will have more electrons than protons so are negative and others will have less electrons than protons so are positive
What is induction and an induced charge
When something is given a positive charge because the electrons in the atoms move away as something negatively charged moves towards them
Give an example of an induced charge
Balloon given negative charge. Balloon pressed by wall and electrons in wall move away, wall now positively charged. Positive and negative attract so they stick together
What is earthing
The process of discharging an object by allowing the extra electrons in it to transfer through metal into the earth
What causes lighting
Lightning is the electrostatic charge built up in clouds discharging through the atmosphere into the earth
What is a bonding line and what is it for
A metal wire connected to an aircraft and the ground before it gets refuelled. This is because fuel can build up electrostatic charge when flowing through the pipe and can cause a spark and ignite if it’s not discharged. The bonding line makes sure the charge doesn’t build up
What are underground fuel tanks metal
So when they are filled, no electrostatic charge can build up as it’s a conductive material
Describe a use of static electricity
Painting parts, the part is given a negative charge and the spray nozzle is connected to the positive terminal, this positively charges the paint droplets so they attract to the part and once they touch, they will become neutral so no more paint droplets will be attracted to that part to allow a mor even coat
Formula for charge
Currant Amps * time seconds
What is currant
The rate of flow of electrons
What is the rule about currant in a circuit
The amount going into a component will be the same coming out of it
What is resistance and unit
How easy it is for currant to flow, measured in ohms
Formula for potential difference
Volts = currant * resistance
How does potential difference affect resistance
The greater it is, the hotter it becomes and the more the resistance
