Electric Field Flashcards
What is Coulomb’s Law
It states that the electric force between 2 point charges is directly proportional to the product of their charges and inversely proportional to the square of their separation
F = (1/4πε.)(Q1Q2/r^2)
What is electric field
An electric field E is said to exist at a region in space if a small positive test charge q placed in it experiences an electric force
What is electric field strength
The electric field strength at a point is defined as the electric for per unit positive charge placed at that point
E=F/q
- q is magnitude of test charge
Properties of electric field lines
- They start on a positive charge and end on a negative charge
- They meet on the surface of charged objects at right angles
- They never cross over one another
- Their density is an indication of the strength of the electric field
- The electric field is uniform between two oppositely charged parallel conducting plates
What is the electric field strength at a point
E = (1/4πε.)(Q/r^2)
The direction of the electric field is the direction of the force that acts on a positive test charge
If 2 or more charges are present, the total electric field = vector sum of the electric fields of the individual charges
What is electric potential
Electric potential at a point is defined as the work done per unit positive charge by an external agent in bringing a small test charge from infinity to that point
V = W/q V = (1/4πε.)(Q/r)
What is electric potential energy
The electric potential at a point is defined as the work done by an external agent in bringing a small test charge from infinity to that point
U=W=qV
U= (1/4πε.)(Qq/r)
What is the relationship between E and V
The electric field strength E at a point is numerically equal to the potential gradient at that point and the direction of the E field point in the direction of decreasing potential V
E = - dV/dr
What is represented by the area under a electric force - distance graph
Work done
What is the electric field inside a conductor
Since there is no charge within the conductor, the electric field is 0 at every point inside the charged conductor
What is the electric field btw charged parallel plates
E = (potential difference across plates)/(plate separation)
E=V/d
What is the relationship btw E and F
F = qE
What is the relationship btw E and V
E = - (dv/dr)
What is the relationship btw U and F
F = -(du/dr)
What is the relationship btw U and V
U = qV
