Chapter 6.2 - Electric Fields Flashcards
Electric Field
A region in which charged bodies will experience a force
What causes an electric field
A charge
How to model a charged sphere
Can be modelled as a point charge when considering outside of the sphere
How electric field lines work
They show the movement of a positive particle. The closer they are the stronger the field.
Basic formula for electric field strength
E = Force per Charge (F/Q)
What is the force between two charges proportional to
The product of their charges,
1 / distance^2
What is the electric field strength proportional to
charge,
1/distance^2
Similarities between an electric and gravitational field in terms of their strength (2)
Both proportional to the value of the charge/mass at a point which is causing the field
Both proportional to 1/r^2
Difference between electric and gravitational fields
Gravitational fields are always attractive whereas electric fields can also be repulsive
Fundamentally what is an electric field
One example of a field giving rise to a force
Equation for electric field strength between to parallel oppositely charged plates
E = V/d
What is special about a uniform electric field
The force/field strength is the same at any point
Motion of a stationary particle when put in a uniform field
Accelerates towards one of the plates depending on its charge
Motion of a particle moving perpendicular to a field that moves into the field
Will continue with same horizontal speed but will accelerate towards one of the plates. Forms a parabola.
Permittivity
Measure of a materials ability to resist an electric field
Equation for capacitor in terms of permittivity
εA/d
How relative permittivity relates to actual permittivity
Multiply relative permittivity by the permittivity of free space (ε0) to obtain actual permittivity
Electric Potential
Work done per unit positive charge to move that charge from infinity to a point in an electric field
Electric Potential Energy of a charged object
The work done to move that charge from infinity to it’s current position
Electric potential at infinity
0
How is potential difference related to electric fields
The electric potential at a point is the potential difference between that point and infinity
How can a charged sphere be a capacitor
It just can idk.
What is the area under a force-distance graph between two points (with regards to electric fields)
The work done to move from one of the points to the other
