Electrostatics Flashcards
What is the electrostatics?
The study of charges at rest
What is the charge of an atom at rest?
Neutral
Are protons and electrons numbers the same?
They are equal
Do atoms have net charge? Explain
No net charge. The overall charge is constant
Explain the structure of an atom
Consists of a central neutral which contains protons and neutrons
What are nucleons?
Protons + neutrons
Which is the nucleus surrounded?
Electrons
What do the positions of the electrons mean?
Electrons can leave or enter an atom. Which change the charge of a neutral atom
How are objects charge?
Objects or charge through friction
Define friction
Resistance to one surface or object encounters when moving over another
When does friction occur?
Occurs when surfaces of two objects are rubbed together
What is the process of electron transfer?
Result of two objects coming into contact with each other
What is separating two objects known as?
The triboelectric charging
What does tribo mean?
To rub
What is the result of the triboelectric charging?
Results in one object gaining electrons on its surface and becoming negatively charged. Another object loses electrons and becomes positively charged
Define triboelectric series
List that runs various materials according to the tendency to gain or lose electrons
What does the top of the triboelectric series mean?
Very positive
What does the bottom of the triboelectric series mean?
Very negative
What happens when an object or atom loses electrons?
They become positively charged as there is a shortage of electrons
What happens when an object or atom gains electrons?
They become negatively charged as there is excess electrons
What can the two types of charges are cause objects to do?
Attract and repel
What is two types of charges attract?
They pull together. One object is positively charged and the other object is negatively charged. Unlike charges attract
What two types of charges repel?
Push away. Both objects are either positively charged or negatively charged. Like charges repel
Before electrons have been transferred what type of charge does an atom have?
Neutral. Equal amount of positive and negative charges
Do protons have the ability to transfer?
No protons are transferred. During the charging process the total number of negative and positive charges remain constant.
What creates the charge of an object to become bigger?
More charges accumulate on the object
When does charges transfer more readily?
Charges transfer more readily when the area is dry as there are no water molecules – third object
What does the type of charge caused by friction depend on?
Depends on the kind of material rubbed together
Define electroscope
Device used to detect the presence of a charge
What is an electroscope constructed with?
Constructed with a metal plate which is the At the top of a metal rod. Thin foil leaves hang from the bottom of the rod. Foil can attract or repel
What happens when the charge is put on the disc or cap?
It spreads down to the plate and leaf. The leaf and plate will have the same charge and therefore the charges will rip out. Delete rises away from the plate
What has to happen for the leave to move further away from the rod?
The bigger the charge the more the leaf rises or deflects
How can the leaf fall again?
By touching the disc or cap, which earths the electroscope. Electrons travel to the next item
What is two ways can an electroscope be charged in?
Contacts and induction
Define contact
Charged rod is touched on the surface of the desk. Some charges are transferred. Same charges as the leaf repels
Define induction
Charged rod is brought close to the desk and then electroscope is earth. The rand is moved
Define the Van De Graaf generator
A machine which uses friction to generate a large buildup of electric charge on a metal dome
What happens when you bring something close to the Van De Graaf generator
You will get shocked
What is the Graaf generator use to demonstrate?
The effects of electrostatic charge
When does the big metal dome become positively charged?
When the generator is on
How can the dome be discharge?
By bringing another insulated metal sphere close to the Dome
Where will the electrons jump once you discharge the Graaf generator?
Electrons will jump to the dome from the metal sphere which causes a spark
When the generator starts charging where does it transfer the charge?
To the person touching it
Why does all the persons hair is repel when they touch the Graaf generator?
They’re all receiving the same charge
What is the principle of conservation of charge?
States that the net charge of an isolated system remains constant during any physical process
Define isolated system
No other thing touching it
What is the rule of electric charge?
It cannot be created nor destroyed it can only be transferred from one object to another
What is the unit of charge?
Coulombs (C)
What is the symbol of charge
Q
When two objects Touch how long do the electrons transfer until?
To object touch the electrons are transferred into objects have the same charge
What happens once the objects have the same charge?
The objects separate
What is the objects separating once they have the same charge known as?
A force of repulsion
What does the total charge before contact equal to?
Total charge before contact = total charge after contact. The total amount to charge in the system remains the same
How do we calculate the charge on each object after they have been touch? Formula
Qnew = Q1+Q2/2
