Term 3 Flashcards
Static electricity
What is lightning?
Lightning is a discharge of static electricity. It either jumps from cloud to cloud or between the cloud and the ground.
What is the definition of static electricity?
It is electricity that does not move along a path.
What is the difference between current and static electricity?
Static electricity does not move along a path and collects on a surface while current electricity flows along a path.
How is static electricity formed/created?
It collects on a surface and is caused by friction or rubbing. (Friction either adds or removes electrons from surface atoms.) - Rubbing to surfaces together.
What causes an object to be either positively or negatively charged?
Either a shortage (positive) or excess (negative) of electrons.
What rule can you follow to determine somethings charge?
Live charges repel and opposites attract.
what happens as a result of electrons repelling one another.
The electrons build up as static electricity and thins electricity is distributed across over the outside of the object which is charged.
What does The Law Of Conservation Of Energy state?
That energy can neither be created nor destroyed, but can only be separated from each other.
Why do charged objects attract uncharged objects?
A negatively charged object will push the electrons to the far side leaving the near side positive. The force is attractive because the positive charges are closer to the rod than the negative charges.
What des your hair stand up when touching a Van de Gaaff generator?
The electrons from the generator flow to the person. They cannot escape to the earth because the person is standing on an insulated layer. The electrons repel each other and flow to the hair. The hairs are now all negatively charged. Since like charges repel the hairs repel each other.
What is electricity?
The movement of charges (electrons or ions) that carry energy through a substance.
what happens when electrons leave an atom?
They either flow as current electricity or build up on the outside of an object as static electricity.
What are the effects of electric current?
Heating ,chemical and magnetic energy.
What are resistors?
They are materials the oppose the flow of current.
What are some good conductors of heat?
iron, copper etc
What are some high resistance metals?
Tungsten and nichrome.
What are examples of energy saving options for lighting?
LED and fluorescent bulbs.
How is an electro magnet formed.
When an electric current passes through copper wire, a magnetic field forms around the conductor.
What makes an electro magnet stronger?
If the wire is coiled around an iron rod. (The magnetic field gets stronger and the rod gets magnetized.)
How do you “turn off” an electromagnet?
Stop the current flowing through it.
How can the strength of an electro magnet be controlled?
- Changing the current
- Changing the number of turn/windings of the coil.
