10: 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 the charges, and inversely proportional to the square of the distance between the charges
What is the equation for Coulomb’s law?
F = 1/4πε0 x Q1Q2/r^2
What is electric field strength (E)?
the force per unit charge experienced by an object in an electric field
What is electric field strength (E) like in a uniform field?
Constant
What is electric field strength (E) like in a radial field?
Variable
What is the general equation for electric field strength?
E = F/Q
What is the equation for electric field strength for uniform fields?
E = V/d
What is the equation for electric field strength for radial fields?
E = 1/4πε0 x Q/r^2
What direction do field lines go for an electric field?
Positive to negative
What is the equation for work done in an electric field?
work done = QΔV
How can you use uniform electric fields to find out if a particle is charged?
- if you fire a particle at right angles to the field and observe its path:
- a charged particle will experience a constant electric force either in or opposite to the direction of the field
- this causes the particle to accelerate and so it follows a parabolic shape
- if the charge is positive it will follow the direction of the field
- if the charge is negative it will move opposite to the direction of the field
What is absolute electric potential (V)?
The potential energy per unit charge of a positive point charge at that point in the field
The absolute magnitude of electric potential is greatest at what part of a charge?
The surface
What happens to electric potential as the distance from the charge increases?
The potential decreases, so the electric potential at infinity is zero
What is the equation of electric potential in a radial field?
V = 1/4πε0 x Q/r
