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MCAT Physical Sciences > Magnetism > Flashcards

Flashcards in Magnetism Deck (16):

Magnetic Fields

Field vectors created by moving charges, currents in wires, and permanent magnets that exert forces on moving charges and permanent magnets.
Units: Tesla = N s/ m C
1 T = 10^4 gauss


Magnetic Force

F = q v B sin θ


What magnitude of force do charges moving parallel to a magnetic field feel?

No magnetic force because the angle is 0 degrees.


Which direction is the magnetic force pointing when a charge is moving towards the top of the page and the magnetic field is pointing into the page?

The magnetic force is towards the left.


Does the magnetic force do work?

No, because the magnetic force on a moving charged particle is always perpendicular to both the velocity of the charge and the magnetic field direction.


What is the centripetal force of a charged particle moving perpendicular to a constant, uniform magnetic field?

Magnetic Force: F = qvB = m v^2/ r


What is the orbit radius for a charge undergoing uniform circular motion due to a magnetic field?

r = mV/ qB


What is the magnetic field for a charged particle moving perpendicular to a constant, uniform magnetic field?

B = mv/ qr



The flow of charge across ΔV, measured by the amount of charge passing through over a unit of time. Electrons from from lower potential to higher potential, but current moves in the direction of positive charge from high to low potential. Therefore, currents in magnetic fields behave similarly to moving positive charges.
I = Δq/ Δt
Units: Ampere = C/ s


Force on a current-carrying wire

F = iLB sin θ


Magnetic Field Lines

Out of the north poles and towards the south poles


Diamagnetic Materials

Diamagnetic material atoms have no net magnetic field, but they will be repelled from the pole of a strong bar magnet.


Paramgnetic Materials

Paramagnetic material atoms do have randomly oriented atomic fields that produce a net magnetic field; however, under certain conditions, the atomic fields can align and the material will be attracted towards a pole of a strong bar magnet.


Ferromagnetic Materials

Ferromagnetic material atoms have magnetic fields when the temperature is below the Curie temperature.


Magnetic Field produced by a current carrying wire

B = μ0 I/ 2πr
μ0 = 4π X 10^-7 T m/ A = 1.26 X 10^-6 T m/ A


Magnetic Field produced by a loop-wire

B = μ0 I/ 2r only at the center of the loop