D.2 Electric and magnetic fields HL Flashcards
What is electric potential energy in the context of charged particles?
Electric potential energy is the energy a system of charges has due to the positions of the charges within an electric field. It is the work needed to assemble the charges from infinite separation.
How is electric potential energy (E_p) calculated for two point charges?
Where k is the Coulomb constant, q_1 and q_2 are the charges, and r is the distance between them.
What does “infinite separation” mean in terms of electric potential energy?
Infinite separation refers to a distance where the electrostatic force between charges is negligible, typically considered to be a few meters for point charges.
Is electric potential energy attributed to individual charges or to the system?
Electric potential energy is a property of the system of charges, not of individual charges. It depends on the relative positions of charges within an electric field.
How does the work done on charges relate to electric potential energy?
The work done on charges, whether moving them closer or apart, is stored as electric potential energy in the system, reflecting energy conservation.
What are equipotential surfaces?
Equipotential surfaces are three-dimensional manifestations of regions in a field where the electric potential is the same at every point. They are perpendicular to electric field lines.
What does it mean if a charge moves along an equipotential surface?
If a charge moves along an equipotential surface, no work is done, as there’s no change in electric potential (ΔV = 0).
How do equipotential lines relate to electric field lines?
Equipotential lines (or surfaces in 3D) are always perpendicular to electric field lines, illustrating the directional nature of potential gradients and electric fields.
What is the work done in moving a charge in an electric field?
The work done (W) is equal to the charge (q) times the change in electric potential (ΔV), represented by W=qΔV.
Describe the electric potential gradient.
The electric potential gradient is the rate at which the electric potential changes with distance. It’s represented by the negative of electric field strength (E), showing how potential varies across space.
