Magnetic Fields Flashcards
What is a magnetic field?
A region of space where a permanent magnet/current-carrying conductor/moving charge experiences a force.
The separation of magnetic field lines indicates _____________ .
the strength of the magnetic field.
A current-carrying conductor has _________ magnetic field lines.
concentric
A current-carrying conductor has concentric magnetic field lines. The direction of the field is given by the ________ rule.
right-hand
The direction of the magnetic field in a solenoid is given by the _______ rule.
right-hand grip
The strength of the magnetic field due to a flat coil or a solenoid may be increased by winding the coil on a __________.
bar of soft iron
This is a coil with a ferrous core.
There is a force on a current-carrying conductor in a magnetic field.
The direction of the force is given by ___________ rule.
Fleming’s left-hand
The magnitude of the force F on a conductor of length L carrying a current I at an angle θ to a magnetic field of flux density B is _________ .
F = BIL sin θ
When using Fleming’s left-hand rule, the thumb points in the direction of the ________ .
motion or force
When using Fleming’s left-hand rule, the first finger points in the direction of the ________ .
magnetic field
When using Fleming’s left-hand rule, the second finger points in the direction of the ________ .
current
Define magnetic flux density.
Force per unit length acting on a long straight conductor carrying unit current perpendicular to the magnetic field.
Unit of magnetic flux density
tesla (T)
Define the tesla.
The magnetic flux density is 1 T when a long straight wire carrying a current of 1 A placed at right angles to the magnetic field experiences a force per unit length of
1 N m-1.
The force on a current-carrying conductor can be used to measure the flux density of a magnetic field using a ________ balance.
current
Magnetic flux density can also be measured with a ____________ .
Hall probe
Explain the forces between 2 current-carrying conductors.
A current-carrying conductor has a magnetic field around it. If a second current-carrying conductor is placed parallel to the first, this second conductor will be in the magnetic field of the first and, by the motor effect, will experience a force. The first conductor will also experience a force. By Newton’s third law, these two forces will be equal in magnitude and opposite in direction.
The force F on a particle with charge q moving at speed v at an angle θ to a magnetic field of flux density B is F = _____
F = Bqv sin θ
A charged particle entering a uniform magnetic field at right angles will move in a _______ path.
circular
arc of a circle
A charged particle entering a uniform magnetic field at right angles will move in a circular path because ____________ .
the magnetic force is perpendicular to the velocity.
For a charged particle moving in a uniform magnetic field, _________ provides the centripetal force.
magnetic force
What is specific charge?
Ratio of charge to mass.
A charged particle is in a region where an electric field and a magnetic field are right angles to each other. The charged particle is undeflected when ___________ is equal to ____________ .
electric force is equal to magnetic force.
Derive an expression for the Hall voltage.
Check notes.