Electric Fields

Question 1

State Coulumb’s law

Answer 1

Coulumb’s Law states that the magnitude of the electric force F, between two point charges Q and q is proportional to their charges and inversely proportional to the square of their seperation r.
F = (1/4πε)(Qq/r^2)
ε is the permittivity of free space or air

Question 2

Define electric field

Answer 2

An electric field is a region of space in which a charge placed in that region experiences an electric force.

Question 3

Define electric field strength

Answer 3

Electric field strength at a point is defined as the electric force exerted per unit positive charge acting on a test charge at that point.
E = F/q = (1/4πε)(Q/r^2)

Question 4

Define electric potential energy

Answer 4

The electric potential energy, U of a charge at a point in an electric field is defined as the work done by an external agent in bringing the charge from infinity to that point.
U = (1/4πε)(Qq/r)

Question 5

Define electric potential

Answer 5

The electric potential at a point in an electric field is defined as the work done per unit positive charge in bringing a small test charge from infinity to that point by an external agent without any change in kinetic energy.
V = U/q = (1/4πε)(Q/r)