Physics II: Magnetism
Summary based on Giancoli 4th Edition
Eric Tüschenbönner
June 2019
List of Constants
Symbol Value Unit
Permittivity of free space 0 8.85 × 10−12 C 2 /N m2
Permeability of free space µ0 4π × 10−7 T m/A
1
, Chapter 27: Magnetism
Magnetic Force
F~ = Il
~ ×B
~ = IlB sin θ (1)
Right hand rule: The given vectors are always perpendicular to each other
Figure 1: Right hand rule to determine vector directions
F~ = q~v × B
~ (2)
Circular path: Magnetic force = centripetal force
mv 2
qvB =
r
mv
r=
qB
Because the magnetic force is always perpendicular to the particle’s velocity, it cannot slow down
the particle. The force cannot do work on the particle as its kinetic energy is maintained.
Lorentz Equation
A particle of charge q moving with velocity v in the presence of both a magnetic field B and an
electric field E, will experience a force:
F~ = q(E
~ + ~v × B)
~ (3)
Torque on a current loop
b b
τ = IaB + IaB = IabB = IAB (4)
2 2
Magnetic dipole moment µ, N is the number of loops:
µ ~
~ = N IA (5)
2
Summary based on Giancoli 4th Edition
Eric Tüschenbönner
June 2019
List of Constants
Symbol Value Unit
Permittivity of free space 0 8.85 × 10−12 C 2 /N m2
Permeability of free space µ0 4π × 10−7 T m/A
1
, Chapter 27: Magnetism
Magnetic Force
F~ = Il
~ ×B
~ = IlB sin θ (1)
Right hand rule: The given vectors are always perpendicular to each other
Figure 1: Right hand rule to determine vector directions
F~ = q~v × B
~ (2)
Circular path: Magnetic force = centripetal force
mv 2
qvB =
r
mv
r=
qB
Because the magnetic force is always perpendicular to the particle’s velocity, it cannot slow down
the particle. The force cannot do work on the particle as its kinetic energy is maintained.
Lorentz Equation
A particle of charge q moving with velocity v in the presence of both a magnetic field B and an
electric field E, will experience a force:
F~ = q(E
~ + ~v × B)
~ (3)
Torque on a current loop
b b
τ = IaB + IaB = IabB = IAB (4)
2 2
Magnetic dipole moment µ, N is the number of loops:
µ ~
~ = N IA (5)
2
