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