Magnetic fields Flashcards
(15 cards)
What is a magnetic field?
a region where a force is exerted on magnetic material
What are field lines?
In which direction do they travel?
what does the separation represent?
magnetic fields
N-S
closer together the lines are the stronger the field
What is Flemming right hand rule?
thumb represents direction of current in a wire, while the first finger represents the direction on the magnetic field
What happens when you put a wire carrying current in a magnetic field?
- the field around the wire and the field from the magnets will interact.
- the field lines from the magnet will contract to form a stretched catapult
- This causes force on the wire
Explain Flemming left hand rule
a current moving from + to - in the direction of your middle finger, in a magnetic field N-S in the direction of your first finger, will cause a force in the direction of your thumb
what does F=BIL mean?
the force on a wire is proportional to the magnetic field strength: when F= force B=the strength of the magnetic field, I=the current. and L=the length of the wire.
Define magnetic field strength (B)
The force on one metre of wire carrying a current of one amp at right angles to the magnetic field
what is another name for magnetic filed strength and what is it measured in?
Flux density, measured in telsas, T
what is one telsa equal to?
the number of flux lines (Wb) per unit area (m^2)
explain F=Bqv
force is equal to Bvq, where B is the magnetic field strength, q is the chaarge on the particle (often the size of the charge on an electron) and v is the velocity
what happens to charged particles in a magnetic field?
they are deflected in a circular path
why are charged particles deflected in a circular path when in a magnetic field?
- the force on a moving charge in a magnetic field is always perpendicular to its direction of travel
- mathematically, this is the condition for circular motion
how and why why are the deflecting effects of charged particles used in particle accelerators?
The RADIUS OF CURVATURE of the path of a charged particle mooing through the magnetic field gives information about the particles charge and mass this means you can identify different particles.
What can magnetic flux be represented as?
The number of field lines
what is magnetic flux equal too?
BA where be B is the magnetic flux density and A is the area
