Electric Potential Energy
1. Coulombs Law
1. Law of Gravity
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3. Electric Potential Energy
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4. Gravitational Force is a conservative force.
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Physics for Scientists and Engineers: Electricity and Magnetism
PHYS 4B

Winter 2016
Physics 4B: Collected Homework 3
Note: magnetic moment of a at loop of wire is = IA where I is the current in the
loop and A is the area of the loop, see page 887 of Serway and Jewett.
1. A charged particle moving along the xaxis in the positive directio
Physics for Scientists and Engineers: Electricity and Magnetism
PHYS 4B

Winter 2016
Physics 4B: Collected Homework 1
1. Coulomb torsion balance. A torsion balance is a device for making delicate measurements of small forces. A horizontal bar is suspended from a torsion bre, which is a
wire or string that has supplies a known torque, per
Physics for Scientists and Engineers: Electricity and Magnetism
PHYS 4B

Winter 2016
* View All
Solutions Here *
11 A rectangular coil of N turns and of length a and width b is
:
rotated at frequency f in a uniform magnetic eld B , as indicated in
Fig. 3038. The coil is connected to corotating cylinders, against
which metal brushes slid
SELFINDUCTANCE
Consider the following circuit:
A. When the switch is closed the current does not reach its max value of I = /R
instantaneously. Faradays Law can be used to explain why this occurs.
B. When the switch is closed the current increases and th
RL Circuits
Consider the RLCircuit shown below with the switch S initially open.
a
S
b
_+
R
+
_
L
_
+
L L
dI
dt
Switch in Position a
V
loop
0
dI
0
dt
dI V IR
dt L L
V IR L
At t=0 when S is closed I 0 :
dI V
At t = 0
dt L
The larger the inductance L, th
ELECTRIC FLUX
Consider a uniform Efield perpendicular to a surface area A.
Recall: Electric Field E
number of electric field lines per unit area.
EA number of Efield lines crossing the surface
EA
Electric Flux
N2
m
C
Electric Flux is proportional to
Electrostatics
The properties of electricity (electric charge) play an essential role in our everyday lives. For
example:
1. Matter is composed of atoms which are in turn composed of electric charges (protons
(positive) and electrons (negative).
2. We wou
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Guasss Law Magnetism
Recall:
Electric Flux
E
E
E dA
net number of electric field lines crossing a closed surface
Magnetic Flux
B
E
B dA
net number of magnetic field lines crossing a closed surface
Consider the closed surface shown above.
Since the net num
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MAGNETISM
Properties of Magnetism Based on Observation
1. There are two magnetic poles A north pole and a south pole.
2. Like poles repel and unlike poles attract.
3. There are no magnetic monopoles.
4.
The direction of the external magnetic field (Bfiel
MAXWELLS DISPLACEMENT CURRENT
A. Recall Amperes Law
P
r
IC
S
B dl
o I c
The line integral of B dl around any closed path equals oIC where IC is the total steadystate
conduction current passing through any surface bounded by the closed path.
B2 r o I c
MAXWELLS EQUATIONS
In 1865 James Clerk Maxwell discovered that the fundamental principles of
electromagnetism can be concisely expressed in terms of 4 equations. We call these
four equations Maxwells Equations:
Gausss Law
E
E dA
qenc
o
Explains how ele
MAXWELLS EQUATIONS
In 1865 James Clerk Maxwell discovered that the fundamental principles of
electromagnetism can be concisely expressed in terms of 4 equations. We call these
four equations Maxwells Equations:
E
E dA
qenc
o
B d o ( I o
B dA 0
E dl
PHYSICS 4B EQUATION SHEET
kq1q2
F12
r
2
Coulombs Law
r12
F
q
E
Electric Field
C
q
r
r2
dq
k 2r
r
2k
r
E
Electric Field due to a
point charge
Eo
k
1
U
CV 2
2
dQ
I
dt
I
J
A
J
E
k
E
E
E
Electric Field due to a
continuous charge
Efield due to infinite line
o