Electric Field Notes
Electric Field
- Electric field is a region in which an electric charge experiences a force.
- Electric field is the amount of electric force on a charged body exerted by external charged bodies.
- Electric field is how charges communicate to one another.
- Charges produce an electric field around them, and other charged particles react to it by experiencing an electric force.
- A charge produces an electric field in its surroundings, but this electric field cannot exert a net force on the charge that created it.
Electric Field and Electric Force
- Electric field at a point P is the electric force (Fe) acting on a positive test charge (q0) placed at that point per unit charge.
- Electric field is a vector quantity with SI unit of newton per coulomb (N/C).
- The electric field equation is: E = \frac{Fe}{q0}
- The equation shows the relationship between electric force and electric field.
- Electric field can be calculated using: E = k \frac{q}{r^2}, where:
- E is the electric field,
- q is the charge that creates the electric field,
- r is the distance between q and the test charge,
- k is the Coulomb constant with a value of 9 \times 10^9 Nm^2/C^2.
- The inverse-square law is applicable to the electric field equation.
Drawing Electric Field Lines
- For a positive charge, the field lines are directed away from the charge.
- For a negative charge, the field lines are directed towards it.
Rules for Drawing Electric Field Lines
- Field lines emanate from the positive charge and terminate at the negative charges.
- Field lines do not intersect at one point; they only meet if the force between the charges is attractive.
- The density of the lines represents the strength of the field.