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Physics 2220
Fall 2012
Paolo Gondolo
EXAM 3
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Student ID Number
Discussion Instructor:
U __ __ __ __ __ __ __
Chad
Chris
Peter
Physics 2220
Fall 2012
Paolo Gondolo
Data: Use these constants (where it states, for example, 1 ft, the 1 is exact for significant figure purposes).
1 ft = 12 in (exact)
1 m = 3.28 ft
1 mile = 5280 ft (exact)

x


x 2  a 2 dx 
1
3

x2  a2

3
1 hour = 3600 sec = 60 min (exact)
1 day = 24 hr (exact)
2
2
gearth = 9.80 m/s = 32.2 ft/s
gmoon = 1.67 m/s2 = 5.48 ft/s2






dx
 x2  a2 
3

x
a2 x2  a2
1 year = 365.25 days
  ax
e
dx


1 kg = 0.0685 slug
1 N = 0.225 pound
1 horsepower = 550 ft‫ڄ‬pounds/s (exact)
24
Mearth = 5.98 × 10 kg
Rearth = 6.38 × 103 km






Msun = 1.99 × 1030 kg





Rsun = 6.96 × 108 m
22
Mmoon = 7.35 × 10 kg
Rmoon = 1.74 × 103 km
G = 6.67 × 10-11 N‫ڄ‬m2/kg2
9
2
2
k = 8.99 × 10 N‫ڄ‬m /C





εo = 8.85 × 10-12 C2/(N·m2)
eelectron charge = -1.60 × 10-19 C
melectron = 9.11 × 10-31 kg





μo = 4π × 10-7 T‫ڄ‬m/A (exact)
N(Avogadro's No.) = 6.02 × 1023 atoms/gm‫ڄ‬mole
26
= 6.02 × 10 atoms/kg‫ڄ‬mole
cos(a ± b) = cos a cos b ‫ ט‬a sin b
xdx
 x2  a 
2 3/2
xdx
a2  x2

1
x2  a2
  a2  x2
dx
 n  x  x 2  a 2 


x2  a2
1  a  x 2  a 2
  n
a 
x
x x2  a2

dx
x a





x
x
 sin 1   , or  cos 1  
a
a
a2  x2
xdx
2
2
 x2  a2
dx
sin(a ± b) = sin a cos b ± sin b
mproton = 1.67 × 10−27 kg
h = 6.64 × 10-34 J
π = 3.14
8
c = 3.00 × 10 m/s









1 Tesla = 10,000 gauss (exact)
ρ(H2O) = 1000 kg/m3
1
  eax
a









dx
1
 n  a  bx 
a  bx b
dx
 a  bx 2

1
b  a  bx 
Physics
Physics2220
2220
Fall 2009Fall 2012
Name: __________________________________
Unid: ___________________________________
Discussion TA: ___________________________
Exam 3
Paolo Gondolo
1
Show all work!! Report all numbers to three (3) significant figures.
The 10-cm wide, zero-resistance slide wire shown in the figure is pushed toward the
2.0 Ω resistor at a steady speed of 0.50 m/s. The magnetic field strength is 0.50 T.
(a)
(b)
(c)
(d)
[10 pts.] How big is the pushing force?
[10 pts.] How much power does the pushing force supply to the wire?
[10 pts.] What is the magnitude of the induced current?
[10 pts.] (2 points for the correct answer and 8 points for explaining your reasoning clearly and correctly) What
is the direction of the induced current? Specify clockwise or counterclockwise.
Physics2220
2220 Fall 2009
Physics
Fall 2012
Name: __________________________________
Unid: ___________________________________
Discussion TA: ___________________________
Exam 3
Paolo Gondolo
2
Show all work!! Report all numbers to three (3) significant figures.
An electric oscillator is made with a 0.10 μF capacitor and a 1.0 mH inductor. At t = 0.0 s, the capacitor is maximally
charged to 5.0 V.
(a)
(b)
(c)
[11 pts.] What are the maximal energies in the capacitor and in the inductor?
[11 pts.] What is the maximum current through the inductor as the circuit oscillates?
[11 pts.] What is the energy in the inductor at t = 31.4 μs?
Physics
Physics2220
220
Fall 2009Fall 2012
Name: __________________________________
Unid: ___________________________________
Discussion TA: ___________________________
Exam 3
Paolo Gondolo
3
Show all work!! Report all numbers to three (3) significant figures.
The maximum electric field strength in air is 3.0 MV/m. Stronger electric fields ionize the air and create a spark.
(a)
(b)
[20 pts.] What is the maximum power that can be delivered by a 1.0-cm-diameter laser beam propagating
through air?
[7 pts.] What is the maximum magnetic field strength in such a laser beam?
Ph~sics
22211
Paolo Gondolo
Fall 2(112
Name:
Rhet+
Unid: _ _ _ _ _ _ _ _ _ _ __
1
Exam 3
Discussion TA: _ _ _ _ _ _ _ _ __
Zero-resistance wires
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Show all work!! Report all numbers to three (3) significant figures.
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The 10-cm wide, zero-resistance slide wire shown in the figure is pushed toward the
2.0 n resistor at a steady speed of 0.50 mls. The magnetic field strength is 0.50 T.
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x x x x x x
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2.0n
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(a)
(b)
(c)
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2220
Fall 2012
Paolo Gondolo
Name: ___
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Vnid: _ _ _ _ _ _ _ _ _ _ __
Discussion T A:
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Exam 3
~---------------­
Show all work!! Report all nnmbers to three (3) significant figures.
An electric oscillator is made with a 0.1 0
charged to 5.0 V.
(a)
(b)
(c)
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capacitor and a 1.0 mH inductor. At t
0.0 s, the capacitor is maximally
[11 pIS.} What are the maximal energies in the capacitor and in the inductor?
[11 pIS.} What is the maximum current through the inductor as the circuit oscillates?
[11 pIS.} What is the energy in the inductor at t = 31.4 j.ts?
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Discussion TA:
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Exan13
~~---------------­
Show all work!! Report all numbers to three (3) significant figures.
The maximum electric field strength in air is 3.0 MV/m. Stronger electric fields ionize the air and create a spark.
(a) (b) f20 pts.] What is the maximum power that can be delivered by a 1.0-cm-diameter laser beam propagating
through air?
.
f7 pis.] What is the maximum magnetic field strength in such a laser beam?
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