Electrostatics And Electroscope Flashcards
Why are living creatures good conductors?
They have a lot of water in their bodies and water is a good conductor
The nervous is system is designed to conduct electrical signals
What are the two groups of materials?
Insulators and conductors
What are insulators?
They are not very good at conducting a charge
What are conductors?
They allow electrons to flow
What are examples of insulators?
Wool
Plastic
What are examples of conductors?
Iron Silicon Alloys Sand Copper Gold Silver
What are the two types of conductors?
Good
Poor
What are poor conductors?
They do not conduct electrons well
What are good conductors?
They do conduct electrons well
What are examples of poor conductors?
Iron
Silicon
Alloys
Soft, thick sand
What are examples of good conductors?
Hard sand
Copper
Silver
Gold
Which material can become electrostatic?
Insulators
Why are insulators the only material that can become electrostatic?
Because friction causes electrons to flow
When they fall on conductors, they flow right through
When they fall on insulators, they build up, causing a negative charge to build up
Why can electrons affect the electroscope?
The metal disc, the rod and the gold leaf are all conductors
How do you draw an electroscope?
A capital T that is five to six lines big
What does polarised mean?
When a single object has a negative charge on the one side and a positive charge on the other side, but the overall charge is still neutral
Why does gold leaf in an electroscope rise when a positive charge is brought near?
Once the electroscope has become polarised, the positive charge in the rod will repel the gold leaf
What is the process of “polarising” called?
Induction
What is conduction?
Charging an object through contact
Why does the gold leaf lift up when a negative charge is brought near to it?
The rod and the gold leaf become negatively charged, so the leaf is repelled
How does an electroscope become charged?
When a charged object is brought into CONTACT with a neutral electroscope, the electrons will jump through the metal disc. The electroscope now has a charge.
Can an electroscope become charged negatively and positively?
Yes, it can work both ways
How do insulators build up an electrostatic charge?
Through friction
Which subatomic particles can move?
Electrons
Can protons move?
No, of course not
How does an insulator gain a positive charge?
It has to lose electrons
How does an insulator become negatively charged?
It needs to gain electrons
How can an object exert an electrostatic force?
It must become charged
What kind of force static is electricity?
Field
What kind of force will two objects with like charges exert on one another?
Repulsion
What kind of force will two objects with unlike charges exert on each other?
Attraction
What kind of force exists between an uncharged object and a charged object?
Attraction
Why will an uncharged object attract a charged object?
When the charged object is brought near to the uncharged object, it will either attract/repel those electrons
The uncharged object has now gained a charge, which will be opposite to the original charged object
These are unlike charges so they will attract
What is the function of an electroscope?
To tell whether an object is charged
To tell what type of charge it carries
What are the parts of an electroscope?
Metal disk Insulator Gold leaf Metal rod Glass Metal box
What is the metal disk for?
To transmit the charge
What is the insulator for?
To ensure that the charge goes directly to the gold leaf
What is the gold leaf for?
It is a good conductor
It is free to move
It will clearly be affected by the charge
What is the metal rod for?
To conduct the charge from the disk to the gold leaf
What is the glass for?
To prevent the leaf from discharging
To allow the viewer to see the gold leaf
What is the metal box for?
To hold the electroscope
What happens when a charged object is brought near to an electroscope?
The charge will travel through the disk, through the metal rod to the gold leaf
The gold leaf and the metal rod will repel each other
The gold leaf will lift up
How does the gold show a stronger charge?
It will lift higher
What will happen to an electroscope when a positive object is NEAR?
The electrons in the base of the electroscope will be attracted to the object
They will move up the rod toward the object
The gold is now positive
The disk is now negative
The metal rod is now positive
The gold leaf will be repelled by the metal rod
It will rise
When the object is removed, the leaf will fall back down
How do we know the electroscope is neutral?
The gold leaf will be hanging down
What will happen to an electroscope when a negative object is NEAR?
The electrons in the metal disk will be repelled
They will move down to the rod and leaf
The disk is now positive
The leaf and rod are negative
They will repel one another
The gold will lift up
When the object is removed, the gold leaf will fall back down
What is important to remember when drawing a polarised electroscope?
The entire electroscope is still neutral
Use vectors to show the movement of electrons
Use vectors to show the movement of the gold leaf
What will happen to an electroscope when a positive object makes CONTACT?
The electrons in the electroscope will jump to the object
The electroscope now has an overall positive charge
The metal rod and the leaf will repel one another
The leaf will lift up
When the object is removed the leaf will still stay up
What will happen to an electroscope when a negative object makes CONTACT?
The electrons in the object will jump to the electroscope
The electroscope now has an overall negative charge
The metal rod and the leaf will repel one another
The leaf will lift up
When the object is removed the leaf will still stay up
Why are the components of an electroscope made of metal?
So that electrons can flow easily
What is earthing?
The process whereby surplus charges can be removed from an object
How can earthing occur?
When a charged object makes contact with a greater object, like the Earth
How does earthing work?
The Earth is big enough to give or take charges without becoming charged, thereby neutralising the object
What does the symbol for Earth look like?
An upside down T with two smaller lines beneath it
What happens when an object is not big enough to “earth” a charged object?
There will be a division of charges
Where does a division of charges occur?
Between two identical objects
What is a division of charges between two identical objects?
When two identical objects touch, they will each try to neutralise each other
If they are not big enough, then there will still be an imbalance of charges
However, the electrons will have divided evenly between the two objects, giving them the exact same charge
