Download Please put away everything except a pen/pencil and a calculator (if

Please put away everything except
a pen/pencil and a calculator (if
you brought one).
No talking, and no using phones/computers
during Quiz!
Mike Czajkowski
Sean Sweeney
Jiahan Zhang
Lecture 15.2 :
Final Exam Review, Part 1
April 25, 2013
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Announcements
•Online Evaluation e-mails should have been sent to you.
‣Please fill out the evaluation form (http://aaf-ratings.syr.edu/)...it is completely
confidential. May 8 is deadline.
‣Remember that PHY212 and PHY222 (lab) are separate courses!
•Society of Physics Student (SPS) is planning to offer “clinic”
services during Finals week. The regular clinic will also be open.
‣Date: May 1st
‣Time: 10am-4pm
‣Location: Rooms 104N and 106 in the Physics building.
• Final Exam is May 6th (a Monday) from 3-5pm.
•Exam #3 Curve: Add 5 points to your score. (e.g. - if you scored a
60%, your curved score is a 65%). Scores currently entered in
Blackboard are not yet curved!
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Course Overview
Exam #1
Exam #2
Exam #3
{
{
{
•Electric Charge and Forces (Ch. 25)
•The Electric Field (Ch. 26)
•Gauss’s Law (Ch. 27)
•The Electric Potential (Ch. 28)
•Potential and Field (Ch. 29)
•Current and Resistance (Ch. 30)
•Fundamentals of Circuits (Ch. 31)
•The Magnetic Field (Ch. 32)
•Electromagnetic Induction (Ch. 33)
•Electromagnetic Fields and Waves (Ch. 34)
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Motivation
What are the overall goals for this course?
Magnets?
Maxwell’s Equations
1.To develop a basic understanding of the laws of electromagnetism.
2.To develop the ability to apply these new concepts to physical situations.
3.To develop an appreciation for the role that electromagnetism plays both
in our modern society and in the universe.
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Model of Electric Charge
Electric Charge is a property of matter.
•
•
•
•
e = fundamental unit of electric charge (not defined yet).
Protons are TIGHTLY bound in nucleus – they don’t go anywhere.
Electrons are more loosely bound.
Object Charge (q) = Npe - Nee = (Np-Ne)e
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Coulomb’s Law
Magnitude of
Electric Force
K = electrostatic constant (8.99×109 N m2/C2)
q1 = charge on particle 1
q2 = charge on particle 2
r = distance between particle 1 and 2
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Electric Field
•source charge creates the electric field, E
•probe charge q within this electric field
experiences a force, F.
•Electric field exists everywhere in space,
regardless of whether there is a probe
charge or not.
•Units: N/C
Electric Field of
Point Charge
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Electric Potential Energy
We derived the potential energy shared by two point
charges by calculating the Work done by one charge on the
other.
Looks like Coulomb’s Law, but it’s different!
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Electric Potential
We introducted “Electric Field” to indicate an
electric charge’s alteration of space. Now we
need a concept of potential energy at all points
in space due to a source charge.
Electric Potential:
Uq+sources
V ≡
q
1 volt = 1 V ≡ 1 J/C
Alessandro Volta
1.5 V Battery
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Example Problem
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Symmetry and Electric Fields
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Electric Flux
Electric Flux = The amount of electric field passing
through a surface.
13
Gauss’s Law
How about the flux of
numerous point charges?
Gauss’s Law
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Gauss’s Law
Examples: Outside a sphere of charge
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Gauss’s Law
Examples: Inside a sphere of charge
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Electric Potential and Field
∆U = −
�
f
i
F� · d�s
V ≡
∆V = −
17
�
f
i
� · d�s
E
� = −∇V
E
Uq+sources
q
Last Lecture...
Capacitance is a
geometric property!
∆VC = Ed
Q
C≡
∆VC
1 farad = 1 F ≡ 1 C/V
Energy Stored in a
Capacitor.
Q
�0 A
C≡
=
∆VC
d
Q2
1
2
UC =
= C(∆VC )
2C
2
For a parallelplate capacitor
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Reminders
•Don’t miss out on opportunities for Final exam
preparation (SPS “clinic”, regular “clinic”, review in
class on Thu./Tue.).
•Final Exam is May 6th from 3-5pm.
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