A-Level Physics: Electric and Magnetic Fields-Overview

what is a force field?

an area in which an object experiences a non-contact force

how can force fields be represented?

as vectors or diagrams containing field lines

what is an electric field?

a force field in which charged particles experience a force

what is electric field strength?

the force per unit charge experienced by an object in an electric field

what is the formula for electric field strength?

force/charge

what does Coulomb’s Law state?

the magnitude of the force between two point charges is directly proportional to the product of their charges, and inversely proportional to the square of the distance between them

what is the equation of Coulomb’s Law?

F= (Q1Q2)/4 x pi x (8.85×10^-12)x radius²

what are the forces between charges of the same sign?

repulsive

what are the forces between charges of opposite signs?

attractive

what forms a radial field?

point charges

what is the equation for the electric field strength in a radial field?

Q/4pi x (8.85×10^-12)xradius²

what is the absolute electric potential?

potential energy per unit charge of a positive point charge at that point in the field

where is the absolute magnitude of electric potential greatest?

at the surface of the charge

what is the value of electric potential at infinity?

zero

what determines whether the value of potential is positive or negative?

the sign of charge: positive charge has a positive potential and is repulsive, negative charge has negative potential and is attractive

how can a uniform field be formed?

by using a pair of parallel plates with a potential difference across them

what is the equation for electric field strength in a uniform field?

voltage/distance

what is the formula of electric potential in a radial field?

charge/4 x pi x (8.85×10^-12) x radius²

what is electric potential difference?

the energy needed to move a unit charge between two points

what do field lines show?

the direction of the force acting on a positive charge

what is the pattern of force created by a uniform field?

force is the same everywhere

what does the magnitude of electric force in a radial field depend on?

distance between the two charges

what does the distance between field lines represent?

magnitude of the force

what happens when a charge moves along an equipotential surface?

no work is done