Electrostatic electricity Flashcards
What is electricity?
- All phenomena caused by positive and negative electrons
- A form of energy
Electricity is most widely used by what?
- Machines of all kinds
- You (your brain)
When is an object positively charged?
When an object has more protons than electrons
What is electrostatic electricity?
The movement of electron charges and keeping balance
Can protons and electrons move?
only electrons
What charges can be transferred between two materials? What charges remain in place?
- negative (electrons)
- positive (protons)
Do charged objects ever return to their natural state?
Charged objects recover their natural state very quickly and will be evenly charged
Opposite charges do what?
Attract
Same charges do what?
Repel
What are conductors?
A material or object that allows for free flow of electrical charge
What are insulators?
A material or object that impedes the free flow of electrical charge
What can negative charges do?
- leave or enter an object creating a net charge on the object
- move within an object that is a conductor disturbing charge within the object
How does an object get positively charged?
Objects lose negative charges/lose electrons
How does an object get negatively charged?
Objects gain negative charges/gain electrons
What are the 3 ways objects can be charged?
- Friction (rubbing)
- Conduction (contact)
- Induction (approaching/close)
Describe the friction of two neutral objects
- Two neutral objects rub against each other
- Friction pulls electrons away from one of the objects transferring them to the other (depending on electron affinity)
- One is positively charged and one is negatively charged (one gained, one lost electrons)
Describe conduction
- Touching of a charged object to a neutral one
- When they touch (and are removed) the charge of one object will be shared between both objects
- They will both have the same charge after
Describe induction
- A charged object getting close to a neutral one
- Get close to exert a power of attraction
- The charged object will cause movement of charges according to the low of charges
- If its +, then + move back and - are at the front
What creates a dipole?
Uneven distribution of charges
What happens when a charges object is brought into contact with the neutral dipole? What is this called?
Conduction
The neutral object will get the same charge as the object that is charged
What happens when a charged object is brought close to the neutral dipole? What is this called?
Induction
The two objects would attract
What happens if a charged object is brought REALLY close to the neutral dipole?
A spark COULD occur between the two objects (electrical discharge) which neutralizes the charge from or to the surroundings
What could make a spark occur? What does this cause?
If a charged object is brought REALLY close to the neutral dipole
This neutralizes the charge from or to the surroundings
What happens if two neutral objects are rubbed together? What is this called?
Friction
If two neutral objects are rubbed together, the negative charges may get transferred from one material to the other
How is the direction of the negative charges determined?
It is determined by how strong each material is attracting them (electron affinity)
What does a high electron affinity mean?
They have a greater pull on electrons
You rub polyester on rubber and rub nylon on gas.
What happens when polyester is then brought in contact with nylon?
Tribo:
polyester, rubber, cotton, fur, nylon, glass
The polyester and nylon will repel eachother
Explain the comb/water thing
check notes but INDUCTION
What is the Coulomb law?
The force between 2 charged objects at rest depends on:
- distance between the objects
- amount of charge on each object
Describe the effect of distance on force between two charged objects
As distance increases, force decreases
Describe the effect of charge on force between two charged objects
As the amount of charge increases, force increases
In Coulomb’s law, what does Fe mean?
Force between the objects (in Newtons (N))
In Coulomb’s law, what does q1 & q2 mean?
amount of charge on the objects (1&2) (in Coulomb (C))
In Coulomb’s law, what does r mean?
Distance between the objects (in metres (m))
What is the charge carried by one electron/proton?
6.25x10^-18 C
What is the unit of measurement for an electrical charge?
Coulomb (C)
What is the k in the force equation calculation?
the constant
(9x10^9) Nm2/C2
Two objects have charges of 5x10^-8 and 2x10^-8. They are 10cm apart.
What is the force between them?
Fe= 9x10^-4 N
Practice Force/Coulomb calculation
check notes
