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Right Hand Rule
These rules should be used to examine the direction of the current, the magnetic field, and the magnetic force.
Physics Fields: a field is a region of space in which a force can act upon
Similarities between Fields
Electrical Fields and Magnetic Fields
Both electrostatic and magnetic forces are attractive and repulsive forces.
Field lines follow a similar pattern. Electric field lines
go from the positive charge to the negative charge. Magnetic field lines go from the north pole to the south pole.
Gravitational and Electrical Fields
Gm1m2/r^2 -- kq1q2/r^2
The formulas for the force of attraction between two charges and two masses happens to be very similar(one common constant, two charges, two masses, and separation distance.
Electric Fields
Coulumb's Law
Describes the force of attraction between two charges
between two same or different charges.
F = kq1q2/r^2
Proportional to the quantity of the charges q1 and q2.
Inversely proportional to the square of the distance between the charges.
Electric Potential Energy
The amount of energy required to move a charge
in the opposite direction of an electric field.
Ug = kq1q2/r; where k is Coulumb's constant,
q1 and q2 are the charges, and r is the distance
between charges
Energy is proportional to the quantity of the charges.
Energy is inversely proportional to the distance of seperation.
Electric Potential(J/C)
Similarly, electric potential is the amount of work
required to move a charge from one point to another.
Electric Field Strength
E: electric field strength, Fe: electrostatic force
q: charge of the source
E = Fe/q (N/C)
Electric Field Lines: Represents the direction and strength
of the electric field with arrows.
Field lines run vertically between parallel plates
, from the positive side to the negative side.
Field lines can extend from positive charges to
the space around the charge.
Field lines can extend from space around the charge to negative charges.
Field lines can extend from positive charges
to negative charges.
The quantity of charge at the source means that there's
a higher line density and more field lines around the charge.
Gravitational Fields
Gravitational Potential Energy (J)
The energy stored in an object depending on the mass and height of the object in relation to the surface of the Earth.
Formula: Ug = mgh
Gravitational Potential (J/kg)
Gravitational potential is the amount of work per
unit mass; it is the amount of work required to move
a mass from a specific point.
Formula: Vg = Eg / m
Attractive Forces between two masses
Fg: force of gravity(N), G: gravitational constant,
m1, m2: masses of two objects(kg), r: distance between objects(m)
Fg = Gm1m2/r^2
Proportional to the masses of the objects.
Inversely proportional to the square of the distance.
Gravitational Field Lines: Represents the direction of the force
vector in a specific field.
Gravitational Field Strength: Force per unit mass
experienced by a mass at a specific point in a field.
g: gravitational field strength(N/kg), Fg: force of gravity(N)
m: mass(kg)
g = Fg / m
Magnetic Fields
Applications
MRI machines
Refrigerators
Speakers and Headphones
Solenoids
A conducting wire that is made into a coil.
The combined fields of all the loops makes up the
overall magnetic field of the coil.
The magnetic field in the coil is uniform at all times.
Magnetic Force
The magnetic force is perpendicular to the direction of the current and the direction of the magnetic field.
q: charge, v: velocity of charge, B: magnitude of
magnetic field, and θ being the angle between v
and B
F = qvBsinθ
Left Hand Rule
Left hand rule should be used when the current is in
electron flow, or from negative charges to positive charges.
Right Hand Rule
Right hand rule should be used when the current is in conventional flow, or from positive charges to negative charges.
Magnetic Field Lines: Represents the direction and strength of the magnetic field with arrows.
Field lines can extend from an area in space to the south
pole.
Field lines can extend from the north pole to an area
in space.
Field lines can extend from the north pole to the south pole.
