Electric Flux and Shielding

Slides:



Advertisements
Similar presentations
Conductors in Electrostatic Equilibrium
Advertisements

Electricity & Magnetism
TOC 1 Physics 212 Electric Flux and Gauss Law Electric Flux Gausss Law Electric Field of Spheres Other Gaussian Surfaces Point Charges and Spheres.
Continuous Charge Distributions
Physics 2102 Lecture 4 Gauss’ Law II Physics 2102 Jonathan Dowling Carl Friedrich Gauss Version: 1/23/07 Flux Capacitor (Operational)
Electric Field Line Patterns Point charge The lines radiate equally in all directions For a positive source charge, the lines will radiate outward.
Conductors in Electrostatic Equilibrium. Electrostatic Equilibrium No net flow of electric charge No current.
Chapter 24 Gauss’s Law.
Chapter 23 Gauss’ Law.
Chapter 24 Gauss’s Law.
Gauss’s Law PH 203 Professor Lee Carkner Lecture 5.
Electricity Electric Flux and Gauss’s Law 1 Electric Flux Gauss’s Law Electric Field of Spheres Other Gaussian Surfaces Point Charges and Spheres.
Chapter 24 Gauss’s Law.
Physics for Scientists and Engineers II, Summer Semester 2009 Lecture 3: May 22 nd 2009 Physics for Scientists and Engineers II.
Electric Forces and Electric Fields
From Chapter 23 – Coulomb’s Law
Electricity & Magnetism Seb Oliver Lecture 6: Gauss’s Law.
Gauss’ Law. Class Objectives Introduce the idea of the Gauss’ law as another method to calculate the electric field. Understand that the previous method.
21. Gauss’s Law “The Prince of Mathematics” Carl Friedrich Gauss
Chapter 24 Gauss’s Law.
Electric Field Lines - a “map” of the strength of the electric field. The electric field is force per unit charge, so the field lines are sometimes called.
Gauss’s law : introduction
Physics Lecture 3 Electrostatics Electric field (cont.)
Physics 213 General Physics Lecture 3. 2 Last Meeting: Electric Field, Conductors Today: Gauss’s Law, Electric Energy and Potential.
Chapter 21 Gauss’s Law. Electric Field Lines Electric field lines (convenient for visualizing electric field patterns) – lines pointing in the direction.
Electric Flux and Gauss Law
Chapter 24 Gauss’s Law. Let’s return to the field lines and consider the flux through a surface. The number of lines per unit area is proportional to.
Lecture 2 The Electric Field. Chapter 15.4  15.9 Outline The Concept of an Electric Field Electric Field Lines Electrostatic Equilibrium Electric Flux.
The Electric Field The electric field is present in any region of space if there exists electric forces on charges. These electric forces can be detected.
Physics 1161 Lecture 4 Electric Flux and Shielding
Physics 2102 Gauss’ law Physics 2102 Gabriela González Carl Friedrich Gauss
Sep. 27, 2007Physics 208 Lecture 81 From last time… This Friday’s honors lecture: Biological Electric Fields Dr. J. Meisel, Dept. of Zoology, UW Continuous.
Copyright © 2015 John Wiley & Sons, Inc. All rights reserved. Chapter 18 Electric Forces and Electric Fields.
18.8 THE ELECTRIC FIELD INSIDE A CONDUCTOR: SHIELDING In conducting materials electric charges move in response to the forces that electric fields exert.
Chapter 18 Electric Forces and Electric Fields The Origin of Electricity The electrical nature of matter is inherent in atomic structure. coulombs.
Property of space around a charged object that causes forces on other charged objects Electric Field.
Slide 1Fig 24-CO, p.737 Chapter 24: Gauss’s Law. Slide 2 INTRODUCTION: In the preceding chapter we showed how to use Coulomb’s law to calculate the electric.
24.2 Gauss’s Law.
Electric Forces and Electric Fields
Electric Forces and Electric Fields
Physics 2102 Lecture: 04 THU 28 JAN
Physics 2102 Lecture: 06 MON 26 JAN 08
Gauss’ Law Symmetry ALWAYS TRUE!
Electric Flux & Gauss Law
Gauss’s Law Electric Flux
Physics 2113 Jonathan Dowling Physics 2113 Lecture 13 EXAM I: REVIEW.
Gauss’ Law Symmetry ALWAYS TRUE!
Reading: Chapter 28 For r > a Gauss’s Law.
Gauss’s Law.
Electrical Field 15.4 Maxwell developed an approach to discussing fields An electric field is said to exist in the region of space around a charged object.
15.6 Conductors in Electrostatic Equilibrium
Active Figure 31.1 (a) When a magnet is moved toward a loop of wire connected to a sensitive ammeter, the ammeter deflects as shown, indicating that a.
Last Lectures This lecture Gauss’s law Using Gauss’s law for:
Chapter 21 Gauss’s Law.
Flux Capacitor (Schematic)
Gauss’s Law Electric Flux
Physics 1161 Lecture 3 Electric Flux and Shielding
Physics 2113 Lecture: 11 MON 09 FEB
Last Lectures This lecture Gauss’s law Using Gauss’s law for:
16 – 3 Electric Field.
Question for the day Can the magnitude of the electric charge be calculated from the strength of the electric field it creates?
The Electric Flux The electric flux measures the amount of electric field passing through a surface of area A whose normal to the surface is tilted at.
The Electric Field The electric field is present in any region of space if there exists electric forces on charges. These electric forces can be detected.
From last time… Motion of charged particles
Fields and Conductors Actually make sense.
Chapter 24 - Summary Gauss’s Law.
Norah Ali Al-moneef King Saud university
Conductors A conductor is a material in which charges can move relatively freely. Usually these are metals (Au, Cu, Ag, Al). Excess charges (of the same.
Electric Fields of Conductors
Physics 1161 Pre-Lecture 4 Charges on Conductors Electric Flux
Presentation transcript:

Electric Flux and Shielding

ALL 3 are true! Preflight 3 -- 1 Which is (are) true? When the charge distribution on a conductor reaches equilibrium, a. the electric field within the conductor is zero. b. any electric charge deposited on the conductor resides on the surface. c. the electric field at the surface is perpendicular to the surface. ALL 3 are true!

Charged Conductors Electrostatic equilibrium is the condition established by charged conductors in which the excess charge has optimally distanced itself so as to reduce the total amount of repulsive forces. Once a charged conductor has reached the state of electrostatic equilibrium, there is no further motion of charge about the surface.

Electrostatic Equilibrium At equilibrium, the charge and electric field follow these guidelines: the excess charge lies only at the surface of the conductor the electric field is zero within the solid part of the conductor the electric field at the surface of the conductor is perpendicular to the surface charge accumulates, and the field is strongest, on pointy parts of the conductor

excess charge lies only at surface of conductor Consider a negatively-charged conductor; in other words, a conductor with an excess of electrons. The excess electrons repel each other, so they want to get as far away from each other as possible. To do this they move to the surface of the conductor.

electric field is zero within the solid part of the conductor They also distribute themselves so the electric field inside the conductor is zero. If the field wasn't zero, any electrons that are free to move would. There are plenty of free electrons inside the conductor (they're the ones that are canceling out the positive charge from all the protons) and they don't move, so the field must be zero.

electric field at surface of conductor is perpendicular to the surface If field at the surface of the conductor weren’t perpendicular to the surface, there would be a component of the field along the surface. A charge experiencing that field would move along the surface in response to that field, which is inconsistent with the conductor being in equilibrium.

charge accumulates, and field is strongest, on pointy parts of the conductor Charge tends to accumulate in greater numbers at locations of greatest curvature.

Shielding A conductor shields its interior from external electric fields. Shielding occurs whether the conductor is hollow or solid. Many electrical devices use this property to shield sensitive circuit elements

Electric Flux θ is the angle between the normal to the surface and the field SI units: N m2/C

Electric Flux

Gauss’ Law Flux through surface of sphere which encloses a charge q In general, flux through a closed surface depends only on enclosed charge.

=2R2E =R2E =0 =(2RL+2R2)E An uncharged cylinder of radius R and length L is immersed in a uniform electric field E. What is the flux of the electric field through the closed surface? =2R2E =R2E =0 =(2RL+2R2)E

=2R2E =R2E =0 =(2RL+2R2)E A cylinder of radius R and length L is immersed in a uniform electric field E. What is the flux of the electric field through the closed surface? =2R2E =R2E =0 =(2RL+2R2)E