P4.2 - Electrical Quantities Flashcards
What’s the relationship between positive and positive charges? [1]
they repel
What’s the relationship between positive and negative charges? [1]
they attract
What’s the relationship between negative and negative charges? [1]
they repel
What happens to the force the closer the charges are? [1]
the greater the force between them
Where do charges come from? [1]
- when two materials are rubbed together
- electrons may be transferred from one to another
What are the charges of the materials being rubbed together? [2]
- one has a net negative charge
- one has a net positive charge
What are conductors? [1]
- materials that let electrons pass through them
What are the best electrical conductors? [1]
- metals
What makes ___ good thermal conductors and why? [2]
- metals
- because they have free electrons
What are insulators? [1]
- materials that hardly conduct at all
Why don’t insulators conduct? [2]
- electrons are held tightly to their atoms
- not free to move
How can electrons be transferred? [1]
by rubbing - static charging
What are examples of insulators? [3]
- plastics
- glass
- PVC
What are semi-conductors? [1]
neither an insulator or a conductor
What are the properties of semi-conductors? [2]
- poor conductors when cold
- better conductors when warm
What is charge measured in? [1]
Coulombs
What is Static Electricity? [2]
- charges which are not free to move
- charges are at rest