All Flashcards
How do you calculate the electric field at a point?
Divide the electric force on a tiny positive test charge by the magnitude of that test charge: .
How to find the net electric field at a point?
Add the individual electric field vectors from all nearby charges. Remember that electric fields are vector quantities.
What is the process of charge redistribution in a conductor?
Conductors rapidly move charges until the electric field inside is zero and charges are at rest.
How to determine the direction of the electric field from a positive charge?
The electric field points radially outward from the positive charge.
How to determine the direction of the electric field from a negative charge?
The electric field points radially inward toward the negative charge.
Given an electric field line diagram around a positive and negative charge, what do the arrows represent?
The arrows represent the direction of the electric field at that point.
In an electric field line diagram, what does the density of the lines indicate?
The density of the lines indicates the strength of the electric field.
In a diagram of a charged conductor, where does excess charge reside?
Excess charge resides only on the surface of the conductor.
In a diagram of electric field lines, what do the starting and ending points of the lines represent?
Field lines start on positive charges and end on negative charges.
In a diagram representing a Faraday cage, what is the electric field inside the cage?
The electric field inside the cage is zero.
Compare charge distribution in conductors vs. insulators.
Conductors: Excess charge resides only on the surface. | Insulators: Excess charge can be distributed throughout the volume and on the surface.
Compare electric fields inside conductors vs. insulators in electrostatic equilibrium.
Conductors: Electric field inside is always zero. | Insulators: Electric field inside can be non-zero.
Compare charge mobility in conductors vs. insulators.
Conductors: Charges move freely. | Insulators: Charges are fixed and do not move freely.
Compare the behavior of electric field lines near positive and negative charges.
Positive charges: Field lines point radially outward. | Negative charges: Field lines point radially inward.
Compare the effect of an external electric field on conductors and insulators.
Conductors: Charges redistribute to cancel the external field inside. | Insulators: Charges do not move freely, so the external field can penetrate.