Electric fields F06-F10 Flashcards
Describe Coulomb’s law of electric force.
The force between two point charges is proportional to the product of charges, and inversely proportional to the square of the distance between the charges.
In Coulombs law of electric force what does a -ve and a +ve force mean?
-ve forces are attraction, +ve forces are repulsions.
What is the equation for Coulomb’s law of electric force?
𝐹 = (1 / 4𝜋𝜀0) x (𝑄1𝑄2 / 𝑟2)
Define ‘electric field strength’.
The force per unit charge felt by a small positive test charge anywhere within that field.
Is field strength a scalar or vector?
Vector
Units of electric field strength?
NC^-1 or Vm^-1
Define ‘electric potential’.
The work done per unit charge to move a small positive test charge from infinity to a point.
Is potential a scalar or vector?
Scalar
Units of potential?
V or JC^-1
How do the field lines indicate field strength?
The closer the lines are together, the stronger the field.
The angle between field lines and equipotentials?
90 degrees always, perpendicular.
How can we use an E vs r graph to find the work done moving between points?
The area under the graph.
How can we use a V vs r graph to find the field strength?
As the electric field strength = E = V/r, therefore it is the gradient from a V against r graph.
What do the field lines in a radial field (around + and - charges) look like?
The same for both, apart from the direction of the force arrows, always positive to negative.
+ Away arrows
- Inwards arrows
What do the equipotential in a radial field look like?
Circles around the charge, equal distances away at each time.
