Topic 6 - Electric and Magnetic Fields Flashcards
(31 cards)
What is the build-up of static caused by?
Friction
Finish the sentence: Electrically charged objects can _______ uncharged objects
Attract
What does too much static cause?
Sparks, as electrons can jump between the object and the Earth due to the different potential differences
How is static electricity used in electrostatic sprayers?
- Spray gun is charged negatively
- Object is given opposite charge
- Paint particles are attracted to the object
- Paint particles repel each other, which gives an even spread
Why can static electricity be dangerous?
The sparks can ignite liquids that are easily flammable
How are the dangers of static electricity dealt with?
Through earthing, as it prevents the build-up of static charge
How does earthing work?
- Connects the static charge to the ground
- Static can go into the ground instead of building up
What do electric charges create?
Electric fields
What is the notation for electric field lines?
- At right angles to the surface
- Go from positive to negative
- The closer they are, the stronger the field is
What do electric fields create?
Electrostatic forces
What does a uniform field look like?
Straight lines, all in one direction, from line a to line b
What does a radial field look like?
Lines coming from all directions to a point in the centre
What is the best example of a radial field?
Gravity acting on Earth
What do magnets produce?
Magnetic fields
Finish the sentence: Magnetic fields produce ______ between magnets
Forces
What are the 3 main magnetic materials?
- Iron
- Nickel
- Copper
What is a permanent magnet?
A magnet that produces its own magnetic field all the time
What is an induced magnet?
A magnet that only produces a magnetic field when it is in another magnetic field. When not in another magnetic field, it is simply just a magnetic material
Give 3 uses of magnetic materials:
- Fridge doors: Permanent magnet strips keep the door closed
- Doorbells: Use of electromagnets that turn on and off rapidly
- Cranes: Use of induced electromagnets to pick up other magnetic materials
What does a moving charge create?
A magnetic field
What is the Right-Hand Rule?
- Point your thumb in the direction of the current
- Curl your fingers
- The direction of your fingers is the direction of the field
What is the Left-Hand Rule?
- First finger = Field direction
- Second finger = Current
- Thumb = Motion/Force
What is a solenoid?
A long coil of wire
What is a solenoid an example of?
An electromagnet
