P4 Flashcards
What is a force?
A push/pull
How does the distance affect force?
All three get smaller as you move further away from the mass/magnet/charge
Describe magnet
An object with a magnetic field
Exert a force on a magnetic material
How do field lines reflect the magnetic strength?
The more denser the field lines are , the stronger the magnetic field
What are permanent magnets?
Always has a magnetic field
Attract/repel other permanent magnetic and also non magnets
How do permanent magnets exert a force on non-magnet?
When brought close , non magnets have magnetism induced in them.
What direction do magnetic field lines go in?
From North Pole to South Pole
Describe the 🌎’s magnetic field
The geographic North Pole is the magnetic South Pole.
Because the magnetic north Pole points to the geographic south Pole
What happens when two magnetic fields interact?
The lines will best around
Creating a high density of field lines between the two magnets, however weak in other places (weak attraction)
What happens when current flows in a wire?
A magnetic field is generated around it
What is a magnetic field?
A region of space within which a magnet experiences a magnetic force of attraction or repulsion.
Describe the look of magnetic fields exist around wires?
Concentric rings
The space between the lines increases with increasing distance
How does a stronger current affect the magnetic field?
Stronger magnetic field
the space between the lines are smaller
What is the corkscrew rule?
RIGHT HAND
Thumb = direction of current
Fingers= direction of magnetic field
What is a solenoid?
A device that increases the strength of the magnetic field around a current carrying wire
How do you make a solenoid?
A wire wrapped many times around a metal that can be magnetised
*not permanent magnets
What is an electromagnet?
A magnet which runs on electricity, the field can be switched on and off
What effects the strength of a solenoid?
🧲coils in the wire
🧲size of current
🧲material of the core inside the wire
How would you show there is a field around a solenoid?
Use iron fillings
What is the relationship between the distance and the strength of a wire?
inversely proportional
The strength is the square of the distance
Eg: double distance , strength decreases by a factor of 4
What is magnetic flux density?
The number of lines of force passing though a unit of area of material
Measured in Tesla’s
Newton per amp meter
What does a circle with an x mean ?
The arrow is going into the page
What does a circle with a point mean?
The arrow is coming towards me
How do you calculate the force on the conductor?
F = BIL
F= force (N)
B= magnetic flux density (T)
I= current (A)
L= length of conductor (m)
What does Flemings left hand rule state ?
The direction of force exerted is always perpendicular to both the direction of the magnetic field and the direction of the current in the wire.
How do you use Fleming’s left hand rule?
Thumb =force
First finger= field
Second finger =current
FFC