Electric fields Flashcards
What is Coulomb’s law?
The magnitude of the force between two point charges in a vacuum is directly proportional to the product of their charges, and inversely proportional to the square of the distance between the charges.
What is electric field strength?
E
The force per unit charge experienced by an object in an electric field.
What are the 3 formulas for electric field strength (E)?
E = F/Q
E = V / d (for uniform fields formed by parallel plates)
Coulombs’ law
What do field lines show?
The direction of the force acting on a positive charge/
What is the formula for work done?
W = F x d
W = Q x delta V
What is absolute electric potential (V) at a point?
The 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 electric potential at infinity?
0
Is the potential positive or negative is the charge is positive?
The potential is positive and the charge is repulsive.
Is the potential positive or negative if the charge is negative?
The potential is negative and the force is attractive (like gravitational potential).
How can you get electric field strength (E) from a V/r graph?
The gradient
What is electric potential difference?
The energy needed to move a unit charge between two points.
What is the formula for work done in moving a charge across a potential difference?
delta W = Q x delta V
What happens when a charge moves along an equipotential surface?
No work is done.
How can you find electric potential difference from an E/r graph?
The area under the graph.
