Static Electricity Flashcards
What is an elctrostatic precipitator
Coal burning power stations produce huge amounts of smoke pollinations which is removed through static electricity . Thin wires are stretched across the centre of the chimney and charged positively. The gas around them becomes positively charged and are then repelled by the wires towards earthed metal plates where the dust sticks a mechanical hammer hits the plate every few miniutes and the ash falls into a bin
How does paint spraying work
The nozzle is charged positively, the droplet of paint are then repelled by each other so the paint spreads out to form a large even cloud. The droplets. Of paint are then attracted to the negatively charged object.
Cellulose acetate
Positively Chatged when rubbed . Insulator
Polythene
Becomes negatively charged when rubbed . Insulator
Sharp points
Loose charge easily. Used in lightning conductor
Gold leaf electroscope is used for
Detecting charge
Charges are measured and stored in
Measures in Columbs stores in capacitators
Conductors allow
Electrons to move through them , insulators do not
What can be made to conduct
Any insulating materials can be made to conduct if voltage is high enough eg lightning and air
What does the charging process do
Transfers electrons
What is static electricity caused by
Frictions
Why does water bend away from negatively charged rod
Electrons in water are repelled and it becomes positive and bends to the rod
What is lightning
Thunderclouds discharging their electricity
How can insulating materials be given charge
By being rubbed
Why does hair stand up when you palace your hand on the van de graaf generator
Charge flows from the Dome to all parts of her body . The pieces of hair are then repelled by each other . The girl stands on an insulator to avoid the Charge escaping through her body and into the earth
How is it possible for a charged object to attract something that is uncharged
Charging by induction e.g negatively charged balloon brought near the wall negative charges are repelled in the wall and the balloon sticks to the wall as it is attracted to the positive charge . Same with paper. Negative charges are repelled from the paper and the paper then sticks to the negatively charged rod.
How come charging by induction works
Because attractive forces are stronger than repulsive forces
What is the issue with pipes and static electricity
When a road tanker pipes oil or petrol into a storage tank , the connecting pipe must be earthed if it isn’t the pipe could become charged . A build up of charge would cause a spark . This could cause an explosion As the fuel vapour Reacts with oxygen in the air .
Why do hospitals need anti static floors
Some of the gases are explosive . If the gas escapes into the air a tiny spark could make it explode . To eliminate static charge in operating theatres antistatic material is used for the flor
What does the gold leaf electroscope consist of
It detects electric charge . Metal plate at the top is connected to the metal rod inside the instrument but insulated from the rest of ye apparatus . Metal rod has a gold leaf attached to it.
Why is the leaf made of gold
Gold can be beaten into very thin sheets
How does the gold leaf electroscope work
It is used to investigate charge on different objects . The electroscope is charged by bringing a positively charged rod close to it , this attracts negative charges towards the metal plate leaving a positive charge on the metal rod and the gold leaf . The leaf is repelled from the rod and rises
How do u Earth the electroscope
Touch it with your finger and excess charge flows through your finger to the earth
Why is the rubber hose of a Petrol can can made of conducting rubber
If the rubbers a conductor charge flows away and will not cause a spark
Why do sharp points loose charge easily
Charge the air . Point at the top of the Lightning conductor lossss electricity to the clouds to neutralise their charge
How does nylon clothing become charged
Charged by frictions of rubbing against your body when you remove the clothes they crackle because of the Sparks of static electricity escaping to the earth
Why do you get a shock after walking on nylon carpet and touching a conductor
You’ve been charged by frictions and the shock is from the charge escaping from you to the conductor
How do ink jet printers work
Inkjet. Directs a fine jet of ink drops onto paper. Each spot of ink is given a charge so that as it falls between a pair of deflecting plates with the opposite charge , electrostatic forces direct it to the correct position. The charges on the plates change hundreds of times each second so that each drop falls in a different position, phoning pictures and words on the paper as required
How do photocopiers work
Positive charges are sprayed onto a rotating drum whose surface is coated with a metal called selenium . A bright light is shone onto the sheets of paper to be copied . The white parts of the paper reflect light onto the drum and the dark or printed places do not. Selenium losses it’s charge when light is reflected onto it . A fine negatively charged carbon powder called toner sticks to the charged parts of the drum . A sheet of paper is pressed against the drum and picks up the pattern of the carbon powder. The powder is then fixed in palace by a heater.
What is the issue with aircraft and static electricity
As aircraft fly through the air they become charged with static electricity there is high potential that a spark is caused during refilling when the charge escapes go the earth , this could cause an explosion. A solution to this problem is to Earth the plane as soon as it lands before refuelling fuel tankers just be earthed before any fuel is transferred to prevent sparks causing a fire or explosion
What is the issue with television screens and computer monitors
They become charged with static electricity as they are used . These charges attracts light uncharged particles that is dust
What is wrong with clothing and static electricity
Our clothing under certain circumstances become charged with static electricity when we remove the clothes there is a possibility of receiving a small electric shock as the charge escapes to the earth
