DOC PREVIEW
SJSU EE 140 - ch23_Electric_Potential

This preview shows page 1-2-3-4-5-6 out of 18 pages.

Save
View full document
View full document
Premium Document
Do you want full access? Go Premium and unlock all 18 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 18 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 18 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 18 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 18 pages.
Access to all documents
Download any document
Ad free experience
View full document
Premium Document
Do you want full access? Go Premium and unlock all 18 pages.
Access to all documents
Download any document
Ad free experience
Premium Document
Do you want full access? Go Premium and unlock all 18 pages.
Access to all documents
Download any document
Ad free experience

Unformatted text preview:

Chapter 23Electric PotentialDr. Ray KwokSJSUElectric Potential - Dr. Ray KwokGoals for Chapter 23• To study and calculate electrical potential energy• To define and study examples of electric potential• To trace regions of equal potential as equipotential surfaces• To find the electric field from electrical potentialElectric Potential - Dr. Ray KwokElectrical Potential Energy similar to gravitational, electrostatic force is a conservativeforce which means there is a potential energy associated with this force such that221e221GrqqkFrmmGF==0dFWnet=⋅=∫lrrdxdUF −=Gravitational forceCoulomb forceor gradient in 3DElectric Potential - Dr. Ray KwokWork and Potential Energy There is a uniform field between the two plates As the charge moves from A to B, work is done on it W = Fd = q Ex(xf– xi) ∆PE = - W= - q Ex∆x Only for a uniform fieldElectric Potential - Dr. Ray KwokPotential Difference (voltage) Potential difference is not the same as potential energy The potential energy and the potential difference are related by : ∆PE = q ∆V Both electric potential energy and potential difference are scalar quantities Units of potential difference V = J/C A special case occurs when there is a uniform electric field ∆V = VB– VA= -Ex∆x Gives more information about units: N/C = V/mElectric Potential - Dr. Ray KwokEquipotential Contour (2D)On a contour map, the curves mark constant elevation; the steepest slope is perpendicular to the curves. The closer together the curves, the steeper the slope.Electric Potential - Dr. Ray KwokEquipotential Surfaces (3D) An equipotential surface is a surface on which all points are at the same potential No work is required to move a charge at a constant speed on an equipotential surface The electric field at every point on an equipotential surface is perpendicular to the surfaceElectric Potential - Dr. Ray KwokEquipotentials and Electric Fields Lines – Positive ChargeThe equipotentials for a point charge are a family of spheres centered on the point charge The field lines are perpendicular to the electric potential at all pointsElectric Potential - Dr. Ray KwokFor two point chargesElectric Potential - Dr. Ray KwokApplication – Electrostatic Precipitator It is used to remove particulate matter from combustion gases Reduces air pollution Can eliminate approximately 90% by mass of the ash and dust from smoke Recovers metal oxides from the stackElectric Potential - Dr. Ray KwokElectric Potential of Point ChargesThe difference in potential energy between points A and B isBoAoBAAoBoABAoBoBA2orqqkrqqkUUrqqkrqqk)UU(rqqkrqqkUdrrqqkrdFW−=−+−=−−+−=∆−=⋅=∫∫rrElectric Potential - Dr. Ray KwokThe Electric Potential of a Point Chargeshown here is V for a positive and negative charge.PE between 2 pt charges:Electric potential from 1 pt charge:rqkVrqqkU21==Electric Potential - Dr. Ray KwokPotential energy curves—PE versus rU > 0 for like charges.U < 0 for opposite charges.F = - dU/drrqqkU21=Electric Potential - Dr. Ray KwokThe Electric Potential of Point ChargesThe electric potential of a group of point charges is the algebraic sum of the potentials of each charge.Electric Potential - Dr. Ray KwokHuman – a complex circuit?ECGAn electrocardiograph plots the heart’s electric potentialElectric Potential - Dr. Ray KwokEEGAn electroencephalograph measuresthe electrical activity of the brain.Electric Potential - Dr. Ray KwokThe Electron Volt The electron volt (eV) is defined as the energy that an electron gains when accelerated through a potential difference of 1 V Electrons in normal atoms have energies of 10’s of eV Excited electrons have energies of 1000’s of eV High energy gamma rays have energies of millions of eV 1 eV = 1.6 x 10-19JElectric Potential - Dr. Ray


View Full Document

SJSU EE 140 - ch23_Electric_Potential

Download ch23_Electric_Potential
Our administrator received your request to download this document. We will send you the file to your email shortly.
Loading Unlocking...
Login

Join to view ch23_Electric_Potential and access 3M+ class-specific study document.

or
We will never post anything without your permission.
Don't have an account?
Sign Up

Join to view ch23_Electric_Potential 2 2 and access 3M+ class-specific study document.

or

By creating an account you agree to our Privacy Policy and Terms Of Use

Already a member?