Karteikarten
Static Electricity
Karten in diesem Stapel (21)
- 1Static ElectricityPhysics 2a 4.1 - 4.3
- 2Describe the structure of an atom.The protons and neutrons make up the nucleus of an atom, these are surrounded by shells of electrons. A proton has a positive charge, an electron has a negative charge and a neutron has no overall charge. Atoms are generally neutral as there are equal protons and electrons.
- 3What happens to an uncharged atom when you add electrons to it?This makes the atom negative, because the atom has more electrons than protons.
- 4What happens to an uncharged atom when you remove electrons from it?This makes the atom positive, because the atom has fewer electrons than protons.
- 5What happens to insulators when they are rubbed with a dry cloth?They become charged.
- 6Give one example of where an insulator becomes charged as a result of friction.By rubbing a polythene rod with a dry cloth, electrons are transferred onto the surface of the rod from the cloth, therefore the rod becomes negatively charged. The cloth is then positively charged as a result of losing electrons.
- 7What is the rule for charges?Like charges repel.
- 8What is current?The rate of flow of electrical charge.
- 9How do metals conduct electricity?Due to free (or delocalised) electrons.
- 10How do conductors hold charge?They can only hold charge if they are insulated from the ground.
- 11How do you charge an insulated conductor?By bringing it into contact with a charged object. If the object is positively charged, electrons transfer from the conductor to the object so the conductor becomes positive. If an object is negatively charged, electrons transfer to the conductor from the object so the object becomes negative.
- 12How do you discharge a charged conductor?You must create a conducting path (eg. wire) between the object and the ground. This allows electrons to transfer between the object and the ground - the object is earthed.
- 13What happens if you supply a conductor with more and more charge?Its electric potential energy increases, the potential difference (ie. voltage) between the conductor and the ground increases.
- 14What causes a lightning strike?This is a dramatic example of where a charged thundercloud can hold no more charge. If the potential difference becomes high enough, a spark may jump between the conductor and an earthed object.
- 15Briefly explain how electrostatics work in a paint sprayer.The spray nozzle is connected to the positive terminal of an electrostatic generator. The negative terminal is connected to the metal panel, the panel then attracts the paint droplets - the droplets pick up the same charge and then repel to form a fine cloud of paint.
- 16How do electrostatic precipitators work?They collect excess ash and dust which threatens to cause global dimming in power stations, the grid wires are negative so the particles become negatively charged when they touch it, the charged particles are attracted by the positively charged plate, they are then shake and removed.
- 17Describe the process of photocopying.There is a positively charged drum which is responsive to light, when light is reflected off the paper onto the drum areas of black do not reflect so the drum keeps its charge in these areas. Black toner sticks to the drum where it is still charged and pressed onto the paper then heated to make it stick permanently.
- 18Give two examples of where electrostatics could be hazardous.1) In pipes.
2) Hospital floors. - 19Explain why electrostatics could cause an issue in terms of pipes.If the pipe connecting the petrol pump and the storage tank is not earthed it could become charged. In which case, a build-up of charge could cause a spark which could then go on to cause an explosion when the fuel vapour reacts with the oxygen in the air.
- 20Suggest why static electricity could be dangerous in hospital.Often anaesthetic gases are used during operations, some of which are very explosive. If the gas escapes into the air, a tiny spark could make it explode.
- 21How do they eliminate these hazards?By implementing antistatic floors, these materials are poor electrical insulators therefore it conducts charge to the Earth.
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- Karteikarten am Static Electricity, erstellt von Lauren Adams am 27/03/2016.
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- Lauren Adams
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