Chapter 10 - fields Flashcards
When is an object affected by a non-contact force
When it is within an area of influence (field)
What part of a magnet generates the force
The poles or ends
How can we tell that an object is under a larger force that one further away
The field lines would be closer together if it is under a larger force
What do field lines show
The magnetic forces, the direction of the force and how that affects objects within the field
What are the 3 things to remember about field lines
- the distance between the field lines represents the strength of the field in that area
- they can never cross one another
- they continue throughout the magnet
Why do like poles repel
The field from one North Pole cannot enter or cross the field of the other north poles and instead the fields move away from each other
What do all metals attracted to metals contain
Magnetic domains
In a piece of magnetised iron how are the domains facing
In the same direction
Why are electromagnets so useful
The strength and direction of their fields can be easily changed
How can the electromagnetic field be strengthened
- by placing an iron core in the middle
- increasing the amount of electricity
- using more wire to create more coils or loops in the spiral
- making electricity flow faster
What can happen if the electrostatic charge is large enough
A spark can be discharged
What does a Vande graff generator do
It separates charge by friction between a moving belt and a plastic pulley
How does a cloud become polarised
Water particles in the cloud bump into each other causing them to lose or gain electrons which results to a temperature difference.
What charge does the upper and bottom part of the cloud have after being polarised
Upper - positive
Bottom - negative
How does lighting occur
The negative and positive charges in the polarised cloud build up and create a large electrostatic field. The electrons quickly move into the positive part of the cloud to balance the charges. This energy is then released as lighting
