ch18 Flashcards
electric field
region of space where a stationary electric charge experiences a force.
electric field strength at a point
the force per unit charge acting on a small stationary positive charge placed at that point
equation of electric field strength
E = F/q where q= positive test charge //// E = V/d
Coulomb’s law
The force between two point charges is proportional to the product of the charges
and inversely proportional to the square of the distance between them
Coulomb’s law equation
F = Q1Q2/(4πε0r^2) or F = kQ1Q2/(r^2)
difference between coulomb’s and newton’s laws
1- The electric force acts on charges, whereas the gravitational force acts on masses.
2- The electric force can be attractive or repulsive, depending on the signs of the
interacting charges, whereas two masses always attract each other.
electric field strength due to the isolated point charge in a vacuum
E = Q/4πε0r^2
The electrical potential at a point in an electric field
work done per unit positive charge in bringing a small test charge from infinity to the
point
The electric potential V
V = Q/(4πε0r)
rate of change of electric potential
potential gradient
link between the electric field strength at any
point and the electric potential gradient at that point
The electric field strength is equal to the negative of the potential gradient at that point.
electric potential energy equation
Qq/(4πε0r)
what is indicated by the direction of an electric field line
direction of force acting on positive charge
how do you know that charges a and b have opposite signs
field doesnt change direction/doesnt become zero
how do you know that charges a and b have same magnitude
minimum is at the midpoint between the charges
