Electric fields Flashcards
Describe Coulomb’s law of electric force
Coulomb’s Law states that the electrostatic force between two point charges is directly proportional to the product of the charges and inversely proportional to the square of the distance between them
Define ‘electric field strength’
Electric field strength at a point is the force experienced per unit positive charge placed at that point in the field.
Is field strength a scalar or vector?
Electric field strength is a vector quantity because it has both magnitude and direction
Units of field strength?
Newtons per coulomb (N/C) or volts per meter (V/m).
Define ‘electric potential’.
Electric potential (𝑉) at a point is the work done per unit positive charge to bring a test charge from infinity to that point.
Is potential a scalar or vector?
Electric potential is a scalar quantity.
Units of potential?
Volts (V)
How do the field lines indicate field strength?
The closer the field lines, the stronger the electric field strength
The angle between field lines and equipotentials?
Field lines and equipotential lines are always perpendicular to each other
How can we use an E vs r graph to find the work done moving between points?
The work done moving between two points in the field is the area under the 𝐸 vs. 𝑟 graph between those points.
How can we use a V vs r graph to find the field strength?
The electric field strength 𝐸 at a point is the negative gradient (slope) of the 𝑉 vs. 𝑟 graph
.
How can we use a V vs r graph to find the work done moving between points?
The work done moving a charge between two points is the difference in electric potential (Δ𝑉) multiplied by the charge 𝑄:
Workdone=Q⋅ΔV
