pan (zp695) – Final exam practice – chiu – (56565)
1
This
printout
should
have
28
questions.
Multiplechoice questions may continue on
the next column or page – find all choices
before answering.
001
10.0points
An electron and a proton are placed at
locations
A
and
B
respectively. At time
t
= 0,
the electron begins to accelerate as shown,
with the magnitude of acceleration being
a
.
If
e
and
m
p
are the charge and mass of a
proton,
r
is the distance between
A
and
B
,
θ
is the angle shown in the figure and
c
is the
speed of light, what will be the magnitude
and direction of acceleration of the proton a
moment after the electromagnetic waves from
the electron reach
B
?
Note:
Vector
vectorr
has magnitude
r
and di
rection pointing from
A
to
B
.
Ignore the
electrostatic force between the electron and
the proton
1.
1
4
πǫ
0
e
2
a
cos
θ
m
p
c
2
r
, parallel to
vectora
2.
1
4
πǫ
0
e
2
a
sin
θ
m
p
c
2
r
, parallel to
vectorr
3.
1
4
πǫ
0
e
2
a
sin
θ
m
p
c
2
r
, perpendicular to
vectora
4.
1
4
πǫ
0
e
2
a
sin
θ
m
p
c
2
r
, perpendicular to
vectorr
5.
1
4
πǫ
0
e
2
a
cos
θ
m
p
c
2
r
, parallel to
vectorr
6.
1
4
πǫ
0
e
2
a
cos
θ
m
p
c
2
r
, perpendicular to
vectora
7.
1
4
πǫ
0
e
2
a
cos
θ
m
p
c
2
r
, perpendicular to
vectorr
8.
1
4
πǫ
0
e
2
a
sin
θ
m
p
c
2
r
, parallel to
vectora
002
10.0points
Two long sheets of width
L
= 2
.
2 cm each
contain
N
= 220 closelypacked wires car
rying current
I
= 12
μ
A in opposite direc
tions. The sheets are separated by a distance
h
= 174
μ
m. Letting the positive
x
direction
be to the right, calculate the magnitude of
vector
B
at point
A
located
y
= 48
μ
m above the exact
center of the lower sheet.
Answer in units of T
003(part1of2)10.0points
The switch below is initially set at position
b
. There is no charge nor current around the
right loop while at position
b
. At
t
=
t
0
the
switch is set to position
a
.
L
R
C
E
S
b
a
c
d
What is the potential difference
V
dc
≡
V
c
−
V
d
across the resistor
R
at
t
=
t
0
?
1.
V
dc
=
∞
2.
V
dc
= 0
3.
V
dc
=
E
e
−
1
4.
V
dc
=
E
(1
−
e
−
1
)
5.
V
dc
=
−E
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
pan (zp695) – Final exam practice – chiu – (56565)
2
6.
V
dc
=
−E
e
−
1
7.
V
dc
=
E
8.
V
dc
=
−E
(1
−
e
−
1
)
9.
V
dc
=
−∞
10.
V
dc
=
E
e
004(part2of2)10.0points
After a long time at position
a
, the switch is
set back to position
b
.
Denote this time as
t
= 0.
What is the maximum energy stored in the
capacitor, expressed in terms of
L
,
E
, and
R
?
(Hint: Use conservation of energy.)
1.
U
max
=
1
2
L
E
R
2.
U
max
=
L
parenleftbigg
E
R
parenrightbigg
2
3.
U
max
=
1
2
L
E
R
2
4.
U
max
=
L
E
R
2
5.
U
max
=
L
E
R
6.
U
max
=
L
E
2
R
7.
U
max
=
1
2
L
parenleftbigg
E
R
parenrightbigg
2
8.
U
max
=
1
2
L
E
2
R
9.
U
max
=
1
2
L
2
parenleftbigg
E
R
parenrightbigg
2
10.
U
max
=
L
2
parenleftbigg
E
R
parenrightbigg
2
005(part1of2)10.0points
A very long glass rod of length 2
R
carries
a uniformly distributed charge +
q
as shown
in the figure.
A very large plastic disk of
radius
R
, carrying a uniformly distributed
charge
−
Q
is located at a distance
d
from the
rod, where
d << R
. Determine the potential
difference Δ
V
rod
=
V
B
−
V
A
due to the long
rod alone.
This is the end of the preview.
Sign up
to
access the rest of the document.
 Spring '08
 Turner
 Magnetic Field, Electric charge

Click to edit the document details