Problem 1.
(a) [13 points] A charge Q is located at the origin and is
separated from a charge 9Q by a distance L along the x-axis.
These two charges are free to move but do not move because
there is a third charge q nearby (not shown).
(i)
Which of the fo

HW 2, Ch.22, due 18th Sept.
PY212
September 11, 2015
1. Some constant and uniform (ie. linear) electric eld of magnitude 12.0 N/C exists in your
lab. You place a at metallic disk of radius 16-cm in the eld, such that the disks normal (
the unit vector whi

HW 3, Ch.23, due 25th Sept.
PY212
September 23, 2015
1. Draw a picture of the equipotential lines of an electric dipole. Relative to innity, the line
between the two charges represents an inection point in the potential, such that it is a
stationary point

9.x}.
HW 2, Ch.22, due 18th Sept.
PY212
September 11, 2015
. Some constant and uniform (is. linear) electric ﬁeld of magnitude 12.0 N/C exists in your
lab. You place a ﬂat metallic disk of radius lﬁ-cm in the ﬁeld, such that the disk’s normal (
the unit v

PY212 Fall 2015
HW 1, due Sep.1l 2015 g0 1“
€21 Ci {fettmi
A negative charge of -0.640uC exerts an upward force of 0.500-N on an unknown charge
|ocated 0.400 m directly above the first charge. What are (a) the value of the unknown
charge (magnitude and si

HW 4, Ch.24 & 26, due 5th Oct.
PY212
September 29, 2015
1. The plates of a parallel-plate capacitor are 3.28 mm apart, and each has an area of 9.82cm2 .
Each plate carries a charge of magnitude 4.35 108 C. The plates are in vacuum. What is
(a) the capacit

HW 5, Ch.26 & 27
due 9th Oct.
PY212
October 4, 2015
1. The capacitor in Fig. P26.70 is initially uncharged. The switch S is closed at t = 0. (a)
Immediately after the switch is closed, what is the current through each resistor? (b) What
is the nal charge

HW 4, Ch.24 & 26, due 5“ Oct.
PY212
September 29, 2015
. The plates of a parallel-plate capacitor are 3.28 mm apart, and each has an area of 9.82mn2.
Each plate carries a charge of magnitude 4.35 x 10—80. The plates are in vacuum. What is
(a) the capacita

PY212 Fall 2015
HW 1, due Sep.11 2015
C.21
1. A negative charge of -0.640 C exerts an upward force of 0.500-N on an unknown charge
located 0.400 m directly above the first charge. What are (a) the value of the unknown
charge (magnitude and sign); (b) the

Problem 1. [20 points]
Three identical point charges q are placed at each of three corners of a square
of side L.
a) Find the electric eld vector at the vacant corner of the square.
b) Find the electric potential at the vacant corner of the square.
A ch

Problem 1. [20 points]
Three identical point charges q are placed at each of three corners of a square
of side L.
a) Find the electric eld vector at the vacant corner of the square.
b) Find the electric potential at the vacant corner of the square.
A char

1
PY212: Electricity, Magnetism, Optics
Lecture 1: Electric charge, Coulombs law
(Young and Freeman, Ch. 21)
Alex Sushkov
asu@bu.edu
This week: discussion sections are on,
homework is due Friday 9/9, 5pm
No labs until week 3
Clickers: register on Black

Problem 1.
(a) [13 points] A charge "Q is located at the origin and is
separated from a charge "9Q by a distance L along the x-axis.
These two charges are free to move but do not move because
there is a third charge q nearby (not shown).
!
!
(i)
Which of

r'which had three components xCM, yCM and ZCM
Name Disc
PY211
Discussion Worksheet 1
Please begin work immediately with your partners on the following.
These exercises are intended to review what you learned about mass distributions, center of
mass, etc

Problem 1. [20 points]
Three identical point charges q are placed at each of three corners of a square
of side L.
a) Find the electric eld vector at the vacant corner of the square.
b) Find the electric potential at the vacant corner of the square.
A ch

Name Disc _ M.
PY212
Discussion Worksheet 3
Please begin working immediately with your partners. + a . an
1. Electric Field and Potential between Parallel Plates A
I . r-D
Two very large sheets of charge are separated by a distance 0'.
One sheet has a sur

PROBLEM 1 6 points
x=0
+2Q
x = 3 cm
-Q
Two charges, +2Q and Q, are separated by 3 cm as shown above. Consider the electric field due to these two
charges, and nothing else.
[2 points] (a) Is there a point along the line passing through the charges, and at

1
PY212
Lecture 2: Electric field
(Young and Freeman, Ch. 21)
Quick quiz:
Three objects are brought close to
each other, two at a time. When
objects A and B are brought together,
they attract. When objects B and C are
brought together, they repel. From
th

1
PY212
Lecture 3: Electric field, Gausss Law
(Young and Freeman, Ch. 22)
q1
q2
Quick quiz:
Examine the electric field lines
produced by the 2 charges in this
figure. Which statement is true?
Homework#2 is due Friday 9/16, 5pm
(a) q1 and q2 have the same

HW 5, Ch.26 & 27
due 9” Oct.
PY212
October 4, 2015
. The capacitor in Fig. P26.70 is initially uncharged. The switch S is closed at t = 0. (a)
Immediately after the switch is closed, What is the current through each resistor? (b) What
is the ﬁnal charge o