Physics Ch 5. Electrostatics and Magnetism Flashcards
Coulomb
The SI unit of charge
Protons
Have a positive charge equal to the fundamental unit of charge, E equals 1.6×10^-19th C
Electrons
A negative charge equal to the fundamental unit of charge, E equals 1.6×10^-19th C
Attractive forces
Occurs between opposite charges
Repulsive forces
Occurs between like charges
Conductors
Allow the free and uniform passage of electrons when charged
Insulators
Resist the movement of charge and will have localized areas of charge that do not distribute over the surface of the material
Coulombs law
Gives the magnitude of the electrostatic force factor between the two charges, the force vector always points along the line connecting the centers of the two charges
Electric field
Is generated by every charge, can exert forces on other charges, is the ratio of the force that is exerted on a test charge to the magnitude of that charge
Field lines
Radiate outward from the positive source charges and radiate in word to negative source charges, represent electric field vectors, positive charges will move in the direction of field lines, negative charges will move in the opposite direction of the field lines
Electric potential energy
The amount of work required to bring a test charge from infinitely far away to a given position in the vicinity of a source charge
Electric potential energy of a system
Will increase when to like charges move toward each other or one to opposite charges move further apart, will decrease when to opposite charges move toward each other or one to like charges move further apart
Electric potential
The electric potential energy per unit charge, different points in the space of an electric field surrounding a source charge will have different values
Voltage
aka potential difference, is the change in electric potential that accompanies the movement of a test charge from one position to another, is path independent and depends only on the initial and final position of the test charge, units are volts
Potential difference
aka voltage, is the change in electric potential that accompanies the movement of a test charge from one position to another, is path independent and depends only on the initial and final position of the test charge, units are volts
Test charges movement
Will spontaneously move in whichever direction results in a decrease in the electric potential energy, positive test charges will move from high potential to low potential and negative test charges will spontaneously move from low potential to high potential
Equipotential lines
Designate the set of points around a source charge or multiple source charges that have the same electric potential, always perpendicular to electric field lines, work will be done when a charge is moved from one equipotential line to another but the work is independent of the pathway taken between the lines, no work is done when a charge moves from point to point on the same equipotential line
Electric dipole
Generated by two charges or opposite signs separated by a fixed distance, d, will experience a net torque in an external electric field until it is aligned with the electric field vector, electric field will not induce any translational motion in the dipole regardless of its orientation with respect to the electric field vector
Magnetic fields
Created by magnets and moving charges, external magnetic fields exert forces on charges moving in any direction except parallel or antiparallel to the field
Tesla
The SI unit for the magnetic field
Diamagnetic materials
Possess no unpaired electrons and are slightly repelled by a magnet
Paramagnetic materials
Possess some unpaired electrons and becomes weekly magnetic in an external magnetic field
Ferromagnetic materials
Possess some unpaired electrons and become strongly magnetic in an external magnetic field
Magnets
Have both a north and South Pole, field lines point from the north to the south pole
Current carrying wires
Create magnetic fields that are concentric circles surrounding the wire
Point charges magnetic field
May undergo uniform circular motion in a uniform magnetic field wherein the centripetal force is the magnetic force acting on the point charge
Magnetic force
The direction of the magnetic force on a moving charge or current-carrying wire is determined using the right-hand rule
Lorentz force
Sum of the electrostatic and magnetic forces acting on a body
Coulombs law equation
Fe = kq1q2/r^2
Electric field equation
E = Fe/q = kQ/r^2
Electric potential energy
U = kQq/r
Electric potential (from electric potential energy) equation
V = U/q
Electric potential (from voltage source) equation
V = kQ/r
Voltage equation
DELTAV = Vb-Va = Wab/q
Electric potential near a dipole equation
V = kqd/r^2*cos(theta)
Dipole moment equation
p = qd
Electric field on the perpendicular bisector of a dipole equation
E = 1/4/pi/epsilon x p/r^3
Torque on a dispole in an electric field equation
tau = pEsin(theta)
Magnetic field from a straight wire equation
B = mu*I/2/pi/r
Magnetic field from a loop of wire equation
B = mu*I/2/r
Magnetic force on a moving point charge equation
Fb = qvbsin(theta)
Magnetic force on a current-carrying wire
Fb = ILBsin(theta)
