Chapter 25
Electrostatic Energy and Capacitance
CHAPTER
25
Electrostatic Energy and Capacitance
1* Three point charges are on the x axis: q1 at the origin, q2 at x = 3 m, and q3 at x = 6 m. Find the
electrostatic potential energy for (a) q1 = q2 = q3 = 2

Chapter 37
Atoms
CHAPTER
37
Atoms
1*
As n increases, does the spacing of adjacent energy levels increase or decrease?
The spacing decreases.
2 The energy of the ground state of doubly ionized lithium (Z = 3) is _ ,where E0 = 13.6 eV.
(a) 9E0, (b) 3E0, (c

Chapter 36
Applications of the Schrdinger Equation
CHAPTER
36
Applications of the Schrdinger Equation
1* True or false: Boundary conditions on the wave function lead to energy quantization.
True
2
Sketch (a) the wave function and (b) the probability dist

CHAPTER
35
Interference and Diffraction
1* When destructive interference occurs, what happens to the energy in the light waves?
The energy is distributed nonuniformly in space; in some regions the energy is below average (destructive
interference), in oth

PHY 207
Test II
June 12, 2000
Name: _
Student ID: _
Answer all four problems. Partial credits are based on the clarity and the quality of the work you
show.
kq
1
E 2 r , k=
=9x109 NM2C-2
4 o
r
F qE
Qin
E
dA =
o
V
kq
r
dV E ( E x dx E y dy E z dz )
d

PHY 207
Test I
May 30, 2000
Name: _
Student ID: _
Answer all four problems. Partial credits are based on the clarity and the quality of the work you
show.
kq
1
E 2 r , k=
=9x109 NM2C-2
4 o
r
F qE
Qin
E
dA =
o
V
kq
r
dV E ( E x dx E y dy E z dz )
dl

CHAPTER
23
11 Show that Ex on the axis of a ring charge of radius a has its maximum and minimum values at x = +a/ 2
and x = a/ 2 . Sketch Ex versus x for both positive and negative values of x.
Take the derivative of Ex given in Equ. 23-10 and set it equa

CHAPTER
24
11 An electron gun fires electrons at the screen of a television tube. The electrons start from rest and are
accelerated through a potential difference of 30,000 V. What is the energy of the electrons when they hit the
screen (a) in electron vo

CHAPTER
26
32 A cube of copper has sides of 2.0 cm. If it is drawn out to form a 14-gauge wire, what
will its resistance be?
L = 8106/2.08106 m = 3.85 m
1. Find the length of the wire; AL = 0.023
2. R = L/A
R = 1.7108 3.85/2.08106 = 0.0314
66 (a) Find th

CHAPTER
4
25
Four point charges of magnitude 2 C are at the corners of a square of side 4 m. Find the
electrostatic potential energy if (a) all the charges are negative, (b) three of the charges are
positive and one is negative, and (c) two are positive

PHY 207
Final
June 23, 2000
Prof. F. Zuo
Name: _
Student ID: _
On my honor, I have neither given nor received any aid on this examination
Signature: _
Answer ONLY five out of six problems. Partial credits are based on the clarity and the quality of
the wo

CHAPTER
22
How many coulombs of positive charge are there in 1 kg of carbon? Twelve grams of carbon
contain Avogadro's number of atoms, with each atom having six protons and six electrons.
5*
Q = 6nCe; nC = NA(mC/12)
Q = (66.0210231031.61019/12) C = 4.82

Chapter 27
The Microscopic Theory of Electrical Conduction
CHAPTER
27
The Microscopic Theory of Electrical Conduction
1* In the classical model of conduction, the electron loses energy on average in a collision because it loses
the drift velocity it had p

Chapter 23
The Electric Field II: Continuous Charge Distributions
CHAPTER
23
The Electric Field II: Continuous Charge Distributions
1* A uniform line charge of linear charge density = 3.5 nC/m extends from x = 0 to x = 5 m. (a) What is the
total charge? F

CHAPTER
24
Electric Potential
1*
A uniform electric field of 2 kN/C is in the x direction. A positive point charge Q = 3 C is released from
rest at the origin. (a) What is the potential difference V(4 m) V(0)? (b) What is the change in the potential
ener

Chapter 26
Electric Current and Direct-Current Circuits
CHAPTER
26
Electric Current and Direct-Current Circuits
1* In our study of electrostatics, we concluded that there is no electric field within a conductor in
electrostatic equilibrium. How is it that

CHAPTER
22
The Electric Field I: Discrete Charge Distributions
1* If the sign convention for charge were changed so that the charge on the electron were positive and the
charge on the proton were negative, would Coulomb's law still be written the same?
Ye

Chapter 28
The Magnetic Field
CHAPTER
28
The Magnetic Field
1* When a cathode-ray tube is placed horizontally in a magnetic field that is directed vertically upward, the
electrons emitted from the cathode follow one of the dashed paths to the face of the

Chapter 30
CHAPTER
Magnetic Induction
167
30
Magnetic Induction
1* A uniform magnetic field of magnitude 2000 G is parallel to the x axis. A square coil of side 5 cm has a
single turn and makes an angle with the z axis as shown in Figure 30-28. Find the m

Chapter 34
CHAPTER
Optical Images
34
Optical Images
1* Can a virtual image be photographed?
Yes. Note that a virtual image is seen because the eye focuses the diverging rays to form a real image on the
retina. Similarly, the camera lens can focus the dive

Chapter 31
Alternating-Current Circuits
CHAPTER
31
Alternating-Current Circuits
Note: Unless otherwise indicated, the symbols I, V, E, and P denote the rms values of I, V, and E and the average
power.
1* A 200-turn coil has an area of 4 cm2 and rotates in

Chapter 29
Sources of the Magnetic Field
CHAPTER
29
Sources of the Magnetic Field
1* Compare the directions of the electric and magnetic forces between two positive charges, which move
along parallel paths (a) in the same direction, and (b) in opposite di

Chapter 32
Maxwells Equations and Electromagnetic Wave s
CHAPTER
32
Maxwells Equations and
Electromagnetic Waves
1* A parallel-plate capacitor in air has circular plates of radius 2.3 cm separated by 1.1 mm. Charge is
flowing onto the upper plate and off

Chapter 33
Properties of Light
CHAPTER
33
Properties of Light
1* Why is helium needed in a heliumneon laser? Why not just use neon?
The population inversion between the state E2,Ne and the state 1.96 eV below it (see Figure 33-9) is achieved
by inelastic