magnetism concept collection…………….

André-Marie Ampére is credited with the discovery of
electromagnetism, the relationship between electric
currents and magnetic fields.
Heinrich Hertz was the first to generate and detect
electromagnetic waves in the laboratory.
Magnetic Force acting on a charge q: [Newtons N]
F = qvBsinq
F = qv ´ B
F = force [N]
q = charge [C]
v = velocity [m/s]
B = magnetic field [T]
q = angle between v and B
Force on a Wire in a Magnetic Field: [Newtons N]
F = BI lsinq
F = I l ´ B
F = force [N]
B = magnetic field [T]
I = amperage [A]
l = length [m]
q = angle between B and the
direction of the current
Torque on a Rectangular Loop: [Newton·meters N·m]
t = NBIAsinq N = number of turns
B = magnetic field [T]
I = amperage [A]
A = area [m2]
q = angle between B and the plane of loop
Charged Particle in a Magnetic Field:
r=mv/qB
r = radius of rotational path
m = mass [kg]
v = velocity [m/s]
q = charge [C]
B = magnetic field [T]
Magnetic Field Around a Wire: [T]
B=₀ I/2r
B = magnetic field [T]
₀ = the permeability of free space 4pi×10-7 T·m/A
I = current [A]
r = distance from the center of the conductor
Magnetic Field at the center of an Arc: [T]
B=₀ I /4 pi r

B = magnetic field [T]
₀= the permeability of free space 4p×10-7 T·m/A
i = current [A]
= the arc in radians
r = distance from the center of the conductor
Hall Effect: Voltage across the width of a
conducting ribbon due to a Magnetic Field:
(ne)V h =Bi
vd Bw =V w
ne = carrier charge density [C/m3]
Vw = voltage across the width [V]
h = thickness of the conductor [m]
B = magnetic field [T]
i = current [A]
vd = drift velocity [m/s]
w = width [m]
Force Between Two Conductors: The force is
attractive if the currents are in the same direction.

F = force [N]
l = length [m]
₀ = the permeability of free space 4p×10-7 T·m/A
I = current [A]
d = distance center to center [m]
Magnetic Field Inside of a Solenoid: [Teslas T]
B = ₀nI
B = magnetic field [T]
₀ = the permeability of free space 4p×10-7 T·m/A
n = number of turns of wire per unit length [#/m]
I = current [A]
Magnetic Dipole Moment: [J/T]
= NIA
= the magnetic dipole moment [J/T]
N = number of turns of wire
i = current [A]
A = area [m2]
Magnetic Flux through a closed loop: [T·M2 or Webers]
= BAcos

B = magnetic field [T]
A = area of loop [m2]
= angle between B and the perpendicular to the plane of
the loop plane of the loop