Electric Fields Flashcards
Electric Charge
A property of matter that causes the particles or objects that possess it to experience a force when near other objects or particles that also possess it. Electric charge is conserved.
Positive Charge
Too few electrons.
Negative Charge
Too many electrons.
Electric Force
Attractive or repulsive force caused by electric charge.
Electrically Neutral
An object with equal amounts of positive and negative charge.
Conductors
Materials such a metals which contain a lot of free electrons.
Insulators
Materials that do not allow the flow of free electrons.
Earthing (or grounding)
The process by which the conductor empties its charge to the ground and becomes electrically neutral.
Electric Field Lines
The lines which positive charges follow. the extend aways from the positive charge and towards the negative charge.
Electric Field Strength
The force per unit charge at a point. Given in N/C.
Uniform Field
The electric field strength is the same at all positions in the field.
Non-Uniform Field
The electric field strength varies with position in the field
Electric Dipole
Two equal and opposite charges separated by a distance.
Electric Potential
The potential energy per unit charge of a positive test charge placed at a point in an electric field. It is a property of the field itself, whether or not a charged object has been placed in in it (measured in J/C=V).
Electric Potential Energy
The energy of a charged object in an electric field (measure in J).
Equipotentials
Lines of constant potential perpendicular to the field lines. Evenly spaces equipotentials gives a uniform field. Unevenly spaced equipotentials gives a non-uniform field.
Potential Gradient
The change in potential per unit distance at a point in a field (given in V/m)
Dielectrics
Insulating materials used to increase the capacity of the plates of a capacitor to store charge for a fixed potential difference. When a dielectric is placed between the charged plates, its molecules become polarised.
Relative Permittivity (or dielectric constant)
The ratio of charge stored with dielectric to charge stored without dielectric.
Capacitance
The charge stored per unit p.d. applied across the plates of a capacitor.
