H213 Electric Fields Flashcards
Define electric field
An electric field is a region of space where an electric charge experiences an eclectic force.
What direction do electric field lines travel in?
Electric field lines travel from a region of higher electric potential to a region of lower electric potential.
Define electric field strength.
Electic field strength E at a point in the field is electric force exerted per unit positive change placed at that point.
Units: [NC^-1] or [Vm^-1]
What is the formula for the electric field strength of a point charge (a single isolated charge) in a free space of air?
E = (1/4piE0)(Q/r^2)
E0 = 8.85 X 10^-12
What is the formula for the electric field strength of a uniform electric field between charged parallel plates?
E = difference in V/d
State Coulomb’s Law
Coulomb’s Law states that the electric force between two point charges is directly proportional to product of the two changers and inversely proportional to the square of separation between the two charges.
State the formula of Coulomb’s Law.
F = (1/4piE0) Q1Q2/R^2
What is the formula of electric potential due to a point charge or spherical charged conductor?
V = (1/4piE0)(Q/r)
What is the electric potential energy of a system of 2 point charges?
U = Q1Q2/4piE0
What is the electric potential of a system of multiple point charges?
Vtotal = (1/4piE0) (Q1/r1 + Q2/r2 + Q3/r3)
What is the electric potential energy of a system of multiple point charges?
Utotal = q(1/4piE0) (Q1/r1 + Q2/r2 + Q3/r3)
What is the relationship between electric field strength and electric potential?
Electric field strength E is numerically equal to the electric potential gradient at a point in the field, negative sign shows that the direction of field strength points towards direction of lower potential.
E = -dV/dr
Define equipotential lines.
Equipotential lines are lines joining points that have the same potential in a field. They always meet electric field lines at right angles.
