Electric Fields Flashcards
Electric field strength E is 0 in a metallic solid sphere
Static charges are equally distributed on the surface of the metallic sphere implies that electric field strength E is 0
why a cable of larger radius will have a smaller electric field strength at its surface
Charges are LESS CONCENTRATED on a larger radius of the cable.
Field lines are more spread out for same potential but larger radius of the cable
Explain why the field strength must be a conductor (by looking at the graph)
Field strength within the sphere is 0
Uniform electric field
The electric field strength is the same at all points in the field
Electric field lines within a uniform electric field are parallel and equidistant,
Explain why gravitational potential are always negative whereas values of electrical potential may be positive or negative
Gravitational force is ALWAYS attractive
work done by external agent is always negative when mass is brought from infinity
Electrical force can be either attractive or repulsive
work done by external agent is positive for charges of the same sign and negative for charges of different sign
Electric potential energy and gravitational potential energy
Electric potential is stored by charges when charges move while gravitational potential energy is possessed by the mass when mass move due to work done in electric and gravitational field respectively
Electric Field lines
Indicated the direction of the force acting stationary positive point charge of the field
Electric Field Strength
The electric field strength at a point is defined as the force per unit positive charge acting on a small test charge placed at a point
Electric Potential
Electric potential, V, at a point in an electric field is the work done per unit
charge by an EXTERNAL AGENT in bringing unit positive charge from infinity to
that point without acceleration.
Coulomb Law
Coulomb’s law states that the electrostatic force between 2 point-charges
is directly proportional to the product of their charges and inversely
proportional to the square of the distance of separation between them,
assuming they are point charges.
Electric potential energy, U
Electric potential energy, U, of a charge at a point in an electric field is
defined as the work done by an external force in bringing that charge from
infinity to that point, without acceleration.
Electric field
An electric field is a region of space in which a charge experiences an
electric force.
With reference to electric field lines, explain why, for points outside an isolated
spherical conductor, the charge on the sphere may be considered to act as a
point charge at its center.
The electric field lines, along which the electric forces exerted by the
charged sphere on other charges act, are always perpendicular to the
surface of the sphere (i.e. the electric field lines are radial).
Hence the field lines appear to originate from the center of the sphere, so
the charge on the sphere may be considered to act as a point charge at its
center.
