To be worked at the blackboard in lecture. R

Slides:



Advertisements
Similar presentations
Sources of the Magnetic Field
Advertisements

A rod is bent into an eighth of a circle of radius a, as shown. The rod carries a total positive charge +Q uniformly distributed over its length. What.
Example: A ring of radius a has a uniform charge per unit length and a total positive charge Q. Calculate the electric field at a point P along the axis.
-L-L L P ConcepTest #5: Assume that a strip of tape, length 2 L, has a uniform charge distribution and is oriented as shown. What is the direction of the.
Radian Measure A central angle has a measure of 1 radian if it is subtended by an arc whose length is equal to the radius of the circle. Consider the circle.
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
Section 5.2 – Central Angles and Arcs Objective To find the length of an arc, given the central angle Glossary Terms Arc – a part of a circle Central angle.
R a d i a n M e a s u r e AREA. initial side terminal side radius of circle is r r r arc length is also r r This angle measures 1 radian Given a circle.
Physics 2113 Lecture 08: MON 02 FEB Electric Fields III Physics 2113 Jonathan Dowling Charles-Augustin de Coulomb ( )
Day 4: Electric Field Calculations for Continuous Charge Distributions A Uniform Distribution of Surface charge A Ring of Continuous Charge A Long Line.
Tue. Jan. 27 – Physics Lecture #23 Electric Field, Continued (and Continuous!) 1. Electric Field due to Continuous Charge Distributions Warm-up: Consider.
Adapted from
The Electric Field Due to a Continuous Charge Distribution (worked examples) finite line of charge general derivation:
Unit Circle. Special Triangles Short Long Hypotenuse s s 2s Hypotenuse 45.
To be worked at the blackboard in lecture.
Magnetic Forces and Fields
Coulomb’s Law (electrical force between charged particles).
Due to a Continuous Charge Distribution
The Electric Field We know that the electric force between charges is transmitted by force carriers, known as “photons”, more technically known as “virtual.
Electric Fields Due to Continuous Charge Distributions
Electric potential of a charge distribution. Equipotentials.
Chapter 23 Electric Potential
Continuous Charge Distributions
Aim: How do we define radians and develop the formula
Fields & Forces Coulomb’s law Q r q How does q “feel” effect of Q?
1.2 Radian Measure, Arc Length, and Area
Magnetic Fields due to Currents
Exam 2: Tuesday, March 21, 5:00-6:00 PM
Course Learning Assistance
That reminds me… must download the test prep HW.
ENE 325 Electromagnetic Fields and Waves
Rotational motion (rotary motion/circular motion/radial motion) An object that rotates about an axis of rotation through an angle q, over a distance s.
Physics 2113 Jonathan Dowling Physics 2113 Lecture 13 EXAM I: REVIEW.
Chapter 22 Electric Fields.
ELECTRIC FIELD ELECTRIC FLUX Lectures 3, 4 & 5 a a R 2R
Chapter 25 Electric Potential.
ELECTRIC FIELD ELECTRIC FLUX Lectures 3, 4 & 5 a a R 2R
Copyright © 2014 John Wiley & Sons, Inc. All rights reserved.
5.3-part 1 The Circular Functions
Announcements Tutoring available
Physics 2102 Lecture: 04 WED 21 JAN
Physics 2113 Lecture 08: FRI 12 SEP
ENE 325 Electromagnetic Fields and Waves
Electric Fields Electric Flux
That reminds me… must download the test prep HW.
Chapter 23 Electric Potential
A ring with radius R has a uniform charge density 
Due to Continuous Charge Distributions
Physics 2102 Lecture 2 Electric Fields Physics 2102 Jonathan Dowling
11.1 Vocabulary Circumference PI () Arc Length Radian.
Physics 2113 Lecture 07: WED 09 SEP
A rod is bent into an eighth of a circle of radius a, as shown
Example: a wire carrying current I consists of a semicircle of radius R and two horizontal straight portions each of length L. It is in a region of constant.
Chapter 22 Electric Fields
Symmetry in Circles Isosceles triangles have two equal sides and two equal angles. e° f° b° 30° n° e = (180 – 30)°  2 m° a° 70° = 75° 110° a = 70°
An infinitesimal length dx of rod has dq=dx of charge, where =Q/L.
Physics 2113 Lecture 07: FRI 30 JAN
Task 1 Knowing the components of vector A calculate rotA and divA.
Physics 2113 Lecture 06 Electric Fields II Physics 2113
Task 1 Knowing the components of vector A calculate rotA and divA.
By Squadron Leader Zahid Mir CS&IT Department , Superior University
3.3 – The Unit Circle and Circular Functions
Chapter 21, Electric Charge, and electric Field
Electrostatics – Charges on Conductors
Chapter 21, Electric Charge, and electric Field
Chapter 23 Electric Field Phys 133.
Chapter 22 Electric Fields
Magnetic Field Due To A Current Loop.
11.1 Vocabulary Circumference PI () Arc Length Radian.
Physics 122B Electricity and Magnetism
Presentation transcript:

To be worked at the blackboard in lecture. R Example: calculate the electric field at “center” of semicircular line of uniformly-distributed positive charge, oriented as shown. +Q To be worked at the blackboard in lecture. R y x You don’t have to follow the steps in the exact order I present here. Just let the problem tell you what to. You may do things in a different order; that’s probably OK. d ds R  dE

Start with our usual OSE. dq ds Example: calculate the electric field at “center” of semicircular line of uniformly-distributed positive charge, oriented as shown. +Q Start with our usual OSE. dq ds d R y Pick an infinitesimal dq of charge. x dq subtends an arc length ds, and an angle d. What is the charge dq?

Draw the dE due to the dq, and show its components. dq ds dq′ R Example: calculate the electric field at “center” of semicircular line of uniformly-distributed positive charge, oriented as shown. +Q Draw the dE due to the dq, and show its components. dq ds dq′ d R y Do you see any helpful symmetry? dE′ dE x Pick a dq′ horizontally across the arc from dq. The x-components of dq and dq′ will cancel. Because of this symmetry, Ex = 0 Each dEy points downward so Ey will be negative.

 is also one of the angles in the vector triangle. Example: calculate the electric field at “center” of semicircular line of uniformly-distributed positive charge, oriented as shown. +Q Recall that dq and ds are infinitesimal. dq is located at an angle  along the semicircle from the negative y-axis. dq ds dq R y  dE x  is also one of the angles in the vector triangle. 

Example: calculate the electric field at “center” of semicircular line of uniformly-distributed positive charge, oriented as shown. +Q An arc of a circle has a length equal to the circle radius times the angle subtended (in radians): dq ds dq R y  dE x  Also,

Let’s summarize what we have done so far. dq ds dq R y  dE x  Every dq is a distance R away from the arc center:

Awesome Youtube derivation: http://www.youtube.com/watch?v=L1n2EUvayfw +Q dq ds dq R y  dE x  Awesome Youtube derivation: http://www.youtube.com/watch?v=L1n2EUvayfw