Statics Flashcards
Where is a neutron found?
Inside the nucleus.
What is a neutrons relative mass?
1
What is the charge of a neutron?
0 - it is neutral.
Where is a proton found?
Inside the nucleus.
What is a protons relative mass?
1
What is the charge of a proton?
1+ - it is positively charged.
Where is an electron found?
Outside of the nucleus.
What is an electrons relative mass?
0
What is the charge of an electron?
-1 - it is negatively charged.
How is an insulator charged?
An insulator can be charged by friction.
- if an insulator rubs against a material and it gains electrons, it becomes negatively charged.
- if an insulator rubs against a material and it loses electrons, it becomes positively charged.
What is induced charged?
The separated charges in the wall are called induced charged.
How can you get an electric shock?
You can get an electrostatic shock if you are electrically ‘charged’ and you touch something that is earthed or if you’re earthed and you touch something that is charged.
Give an example where you can get an electric shock from an everyday object:
For example, when you walk on a vinyl floor or one covered with a nylon carpet you ‘charge up’ because of friction. You can earth yourself, and so get an electrostatic shock by touching a metal door handle, water pipe or even another person.
Give an example of how you can get an electric shock from lightning:
Lightning occurs when charge builds up within a cloud. When the charge is large enough, it leaps to another part of the cloud, or to the ground/
What is earthing?
Most objects can be made safe by earthing. Earthing involves placing a metal conductor between the object and the Earth to channel the charges safely to Earth.
What is a gold-leaf electroscope?
A gold-leaf electroscope is used to find the charge on an insulator. A metal rod connects a metal cap to gold leaf.
What happens if you bring negatively charged rods towards the gold-leaf electroscope?
Bringing a negatively charged rod close to the cap will repel the electrons down the metal rod. The gold leaf moves away from the metal rod because they both have the same charge. The greater the charge, the further away the leaf moves.
What happens if you bring positively charged rods towards the gold-leaf electroscope?
Bringing a positively charged rod close to the cap will attract the electrons towards the cap, leaving the gold leaf and the metal rod with a positive charge. Again, the gold leaf moves away from the metal rod because they both have the same charge.
What are the uses of electrostatics?
- paint sprayers
- insecticides
- photocopiers and laser printers
- defibrillators
- electrostatic dust precipitators
How can you use electrostatics in paint sprayers?
- the object to be sprayed,such as a car, is connected to a negative supply
- the sprayer charges the tiny droplets of paint as they emerge from the nozzle
- the charged droplets of paint repel each other and spread out to form a dispersed cloud
- the positive droplets are attracted to the negatively charged object being sprayed
What are the advantages of using electrostatics in paint sprayers?
- less paint is used
- the object is given an even coat of paint
- every part of the object attracts the paint, even the underside
How can you use electrostatics in insecticides?
The same technique is used as the paint sprayer. The insecticide is given a positive charge and the plants acquire a negative charge by induction.
What are the dangers of electrostatic charges?
- certain clothing fibres can rub together and cause charges to separate.
- if you bring your fingers close to a charged insulator, the electrons on the surface will jump the tiny distance of air and travel through you to the Earth.
- you can get electrical shocks from everyday objects (walking on nylon carpets, touching a metal tap or radiator or clothing becoming charged from a seat belt/car seat).
- fuelling aircraft and tankers cause static as the fuel rubs against the pip. The charges can build up and create and spark igniting the fuel.
- lightning during thunderstorms can destroy buildings and start forest fires.
How can the dangers be minimised?
The dangers can be minimised by using earthing.
