Electricity And Magnetism Flashcards
…. Always move in a direction that will increase their potential
Electrons
Materials that contain many electrons inside theme
Conductors
Charges in coulomb law are assumed to be
Point charges
Force per unit charge experienced by a small positive test charge
Electric field
The electric field inside any conducting body is … Because of situations in which charge does not move
Zero
…. Charge electric field lines are directed into the charge
Negative
An … Has constant magnitude and direction
Uniform
An electric charge creates an electric field and an …. Around it
Electric potential
The … At a point is the work per unit charge that must be done to bring the positive test charge from away to the point of interest
Potential
Electric field between parallel lines can be defined as
E=V/d, where V is potential difference and d is the separation
The work done when a charge equal to 1e is taken across a potential difference of 1 volt
Electron volt
A moving charge creates an
Electric current
The presence of an electric field inside a conductor forces electrons to accelerate in a direction opposite to the field (why?) and this orderly motion of the electrons in the same direction is what makes electric current
The charge of the electron is negative
… Lose energy constantly, which…. Pick about. These will vibrate about their equilibrium positions, which will increase the temperature of the material
Electrons / atoms of the material
An electric current is produced when a wire is heated so that it begins to emit electrons
Thermionic emission
Potential difference across its ends, divided by the current flowing through it
Electric resistance
When the temperature of a metallic conductor is kept constant, the current through it is proportional to the potential difference across it
Ohm’s law
The… Of a wire is proportional to its length L and inversely proportional to the cross sectional area A
Resistance
If a current flows through a resistor, then there must be a potential difference across the ends of that resistor. A resistor is thus said to
Drop the potential
In a battery, work must be done on the electrons to push them from the positive to the negative terminal. The ratio of work done by non electrical forces to a quantity of charge q that moves from one terminal to the other is the
Emf of the battery
An … Measures the current in the resistor connected in series to it
Ammeter
Measures the potential difference across a resistor it is connected parallel to
Voltmeter
The fact that the magnetic force on a charge is always normal to the velocity means that the path of a charge in a magnetic field must be
Circular or helical
The magnitude of the magnetic field B created by a current in a wire varies linearly with the current in the wire and inversely with the perpendicular distance from the wire
Orsted
The constant of proportionality between magnitude of magnetic field, current and distance is
Magnetic permeability of vacuum
Forces are attractive in
Parallel currents
Forces are repulsive in
Antiparallel currents
Magnetic forces must be equal in magnitude even though the magnetic fields are different
Newton 3
