Electric and Magnetic Fields Flashcards
What is causes static charge?
Friction
If you rubbed metal with a cloth, would you get static charge.
No, because 2 insulators must be rubbed together to create a static charge
How do plastic rods become positively charged?
When They are rubbed by a cloth, the electrons are rubbed off the plastic rod and transferred onto the cloth, making the rod positively charged.
Gives one use of static charge.
Electrostatic sprayers
Photocopiers
Give two dangers of static charges.
Sparks when refuelling cars and airplanes, lightening
How does earthing things reduce the risk of a spark
It is allows the charge that built up to escape, isolating the system.
Do electronic field lines go from positive to negative or negative to positive.
Positive to negative
Do magnetic field lines do form S to N or N to S.
N to S
What can be used to show the magnetic field lines?
Iron filings or a plotting compass.
Give the only 3 metals that are magnetic.
Iron, Nickel and cobalt
Give 5 uses of magnets
Fridge doors, Cranes, Maglev trains, MRI scanners and doorbells
What is the Right Hand Rule?
Thumb shows direction of current and fingers the direction of the field.
What does each finger in the Left Hand Rule represent/
Thumb is the Motion, First Finger is the Field and The second finger is the Current.
What is the equation to find the Force acting on a wire at 90 degrees to the field.
F=BIl
Calculate the force on a 20cm wire if 1.2A of current is flowing and the magnetic flux density is 0.5T.
0.12N
