Electric Field Models The electric field of a point charge q at the origin, r = 0, is where є0 = 8.85 × 10–12 C2/N m2 is the permittivity constant. The direction of field determined by motion induced on a positive test charge.

Electric Field Models The net electric field due to a group of point charges is where Ei is the field from point charge i.

E- Field and G- Field Electric field is electric force per unit charge. What is the analogous quantity for gravitational force? Derive a mathematical expression for gravitational field. Have you seen this quantity before? General Physics 2 Electric Field

Electric Field Lines What would the electric field lines look like for a uniform electric field? General Physics 2 Electric Field

Electric Field North South East West A proton is released in a uniform electric field, and it experiences an electric force toward the south. What is the direction of the electric field? North South East West

Electric Field North South East West An electron is released in a uniform electric field, and it experiences an electric force toward the west. What is the direction of the electric field? North South East West

Electric Field 3.2x10-16, east 3.2x10-16, west 8.0x10-23, east What are the magnitude and direction of the electric force on an electron (e=1.6x10-19 C) in a uniform electric field of strength 2000 N/C that points due east? 3.2x10-16, east 3.2x10-16, west 8.0x10-23, east 8.0x10-23, west

Calculate the electric field 0.1 m from a 10-6 C charge. General Physics 2 Electric Field

The Electric Field of a Dipole We can represent an electric dipole by two opposite charges ±q separated by the small distance s. The dipole moment is defined as the vector The dipole-moment magnitude p = qs determines the electric field strength. The SI units of the dipole moment are C m.

- + Electric Field Lines Draw field lines for the following charge distributions - + General Physics 2 Electric Field

- - Electric Field Lines Draw field lines for the following charge distributions - - General Physics 2 Electric Field

The Electric Field of a Dipole The electric field at a point on the axis of a dipole is where r is the distance measured from the center of the dipole. The electric field in the plane that bisects and is perpendicular to the dipole is This field is opposite to the dipole direction, and it is only half the strength of the on-axis field at the same distance.

EXAMPLE 27.2 The electric field of a water molecule QUESTION: 1.1 x 10^8 N/C

The Electric Field of a Continuous Charge Distribution The linear charge density of an object of length L and charge Q, is defined as Linear charge density, which has units of C/m, is the amount of charge per meter of length.

An Infinite Line of Charge A very long, thin rod, with linear charge density λ, has an electric field Where r is the radial distance away from the rod. Field lines perpendicular to rod surface. Field decreases with distance.

Think-Pair-Share Q1 = -1x10-6 C Q2 = 10 x 10-6 C Two charges, Q1 and Q2, are separated by 100 nm. What is the electric field midway between the charges? Two charges, Q1 and Q2, are separated by 100 nm. Where on the line joining Q1 and Q2 is the electric field equal to zero? General Physics 2 Electric Field

Workbook p. 27-3, 27-5, 27-6 Electric Field is a Vector Challenge: What is the net Electric field at point A? What is the net force on a charge Q that is placed at A? Derive the electric field of a line of charge of length L P Total charge +Q General Physics 2 Electric Field