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Unformatted text preview: PHYS 202 (Sec. 2) 4“ i9): w TEST 1 March 13, 2000 INSTRUCTIONS NOTE: YOU LOSE 5 POINTS IF YOU FAIL TO FOLLOW ANY OF THESE INSTRUCTIONS. i.
2.
3. Answer this test on the furnished SCANTRON card (or its equivalent) using a #2 pencil.
In the blank labeled “NAME” on the SCANTRON card. print your name. Read the directions in the box labeled “IMPORTANT” on the SCANTRON card. Note that you must erase
pencil marks completely when changing your entries. Following the instructions in the box labeled “PART 1“ on the SCANTRON card, write your ninedigit ID
number in the appropriate spaces, starting at the top row. Code your ID by marking through the correct numbers
as instructed. The bottom row in the ID box should be left empty. Each question in the attached test has a corresponding row on the SCANTRON labeled by the question numbers
“1 etc. Mark through the letter on the SCANTRON card corresponding to your answer for that question.
You lose 10 points for each question in which you mark a wrong answer, no answer, or more than one answer.
In numerical problems, mark an answer if it is within 10% of your answer. When you are through, double check your marks and erasures! Also, be certain your answers are in the rows
corresponding to the question numbers on the test. Turn in only the SCANTRON card u 1 The magnetic energy stored in a certain inductor is 3.00 J when the current through it is 4.00 A. Calculate the
inductance. CAD 24.0 H CB: 0.750 H 9
CC:I 1.50H $9 0.375 H CE 3 None of the above 3.1m = :1; L I2 as
current I as magnet as magnet
decreases leaves loop enters loop as switch closes as switch opens 3 A constant current ﬂows through a certain light bulb. During a 3.00s time interval, 50.0 C of charge ﬂows thr ugh the bulb. What is the current through the bulb? ﬁlSOA I=% ﬁg, 333 he"?
B: 0.060A 3 5C3 810 A CD: 0.180 A “EllNone of the above 4 A very long straight horizontal wire carries a current of 20.0 A toward the north. What are the magnitude and
direction of the magnetic induction at a position 3.00 to directly above the wire? 13h! 1.33 X 10‘5 T, east
:33 4.19 X 10—6 T, east
CC:I 1.33 X 10"6 T, down
IIDS! 4.19 X 10‘6 T,d0\vn E E 3 None of the above 5 The electromotiveforce (emf) of a device is deﬁned as
CA3 the maximum current it can deliver to a circuit. BBB the nonelectrostatic work per unit charge it performs in moving charge from one of its terminals to the
other. I:CD the electrostatic force per unit charge it exerts in current leaving its positive terminal.
C D 3 the maximum force it exerts in the charges it creates within itself. E E 3 the product of the internal resistance of the device and the current ﬂowing through the device. 6 A very long cylindrical copper rod of radius 5.00 x 10'2 m carries a current of 400 A. The current density is
uniform throughout its cross section. What is the magnitude of the magnetic induction at a point inside the rod
3.00 X 10'2 In from its axis? .05 :A: 3.02 x 10—41"
Ian 9.60 x 104 T
*3 8.38 x 10‘1 T
CD: 4.44 x 1031‘ I: E 3 None of the above Us I.
am 7 If you multiply the area of a ﬂat current loop by the current ﬂowing through the loop, the quantity you get is the
magnitude of the I2A3 the magnetic induction at the center of the loop.
EB 3 the torque on the loop. 7 I0“ magnetic dipole moment of the loop. EDD the magnetic ﬂux enclosed by the loop. CE :1 the emf induced around the loop. 8 What is the magnitude of the magnetic force on a proton moving at 8.00 X 106 m/s perpendicular to a magnetic
ﬁeld whose magnetic induction is of magnitude 0.500 T?
EA: 4.00x106N F‘ i W B We 4 Mimosa :3: 2.56 X1042N r L 1
Cc: ZSOX 102m Ir) {l:(.04 lo' c)(3.t>oxlo°%)( ,5 7)
CD: 1.00 x 1026N
* None of the above 9 The magnetic ﬂux @(t) enclosed by a square at timer is given by (110) = (5.00 Wb/s3)t3. What is the absolute
value of the emf induced around the square at time t = 2.00 s? I:A:l 5.03 X IO‘5V /( 73a“ 5H) t"
slim 40.0v ms .14
cc? 7.54 x 10"V lam 600V EEj None of the above 10 What is the equivalent resistance of a series combination of a 6.004). resistor and an 800!) resistor?
«A: 14.00 W‘~*~—’W—*
C B 3 3.43 .0.
CC: 0.292 .0.
CD 3 7.00 .0. CE 3 None of the above m 51‘ Pm m a? f L} IL I.“
Q
SCRATCH SHEET
Information you may or may not need: FB = K; V X 13 f: f (M x B ,3 . M, I J! z ,3
gravitational acceleration near earth = 9.80 mls2 mm M g” 4"
magnitude of electronic charge = 1.60 X 10'19 C
mass of electron = 9.1 l X 10‘“ kg P — 39.1.
mass of proton: 1.67 X 10‘27 kg UT : 3 (air) “7"”
permittivity of vacuum = 8.85 X 10'12 Flm O “(A I
permeability of vacuum = 47: X 10—7 TmIA a”;
o éean
A 5A B — MD rcwj
J
L. L I l_ :4." .9 LI" w_.,EaLrg. PHYS 202 (Sec. 1) TEST 2 October 12, 2005 INSTRUCTIONS
NOTE: YOU LOSE 5 POINTS IF YOU FAIL TO FOLLOW ANY OF THESE INSTRUCTIONS. 1. Answer this test on the furnished SCANTRON card (or its equivalent) using a #2 pencil. 2. In the blank labeled “NAME” on the SCANTRON card, print your name. 3. Read the directions in the box labeled “IMPORTANT” on the SCANTRON card. Note that you must erase pencil
marks completer when changing your entries. 4. Following the instructions in the box labeled “PART 1 ” on the SCANTRON card, write your ninedigit ID number
in the appropriate spaces, starting at the top row. Code your ID by marking through the correct numbers as instructed. The bottom row in the ID box should be left empty. 5. Each question in the attached test has a corresponding row on the SCANTRON labeled by the question numbers
“1”, “2”, etc. Mark through the letter on the SCANTRON card corresponding to your answer for that question.
You lose 10 points for each question in which you mark a wrong answer, no answer, or more than one answer. In
numerical problems, mark an answer if it is within 10% of your answer. 6. When you are through, double check your marks and erasures! Also, be certain your answers are in the rows
corresponding to the question numbers on the test. ' 7. Turn in only the SCANTRON card. ,EtﬂaI ‘Y; The electromotiveforce (emf) of a device is deﬁned as
E A3 the maximum current it can deliver to a circuit.
‘9' the electrostatic force per unit charge it exerts in current leaving its positive terminal. @e nonelectrostatic work per unit charge it performs in moving charge from one of its terminals to the other.
'2 D:I the maximum force it exerts in the charges it creates within itself.
E E 3 the product of the internal resistance of the device and the current ﬂowing through the device. I
¥ The (sewinductance of a component is deﬁned as C A 3 the absolute value of the ratio of the potential difference across the component divided by the current ﬂowing through the component. éi: — L OR —— in
d ’e
*’>C B:I the absolute value of the ratio of the selfinduced emis across the component divided by the time rate of change of current ﬂowing through the component.
I.— the negative time rate of change of magnetic ﬂux enclosed by that component. I: D:I the voltage across the component multiplied by the time rate of change of the current ﬂowing through the
component. C E 1' the current induced in the component when the magnetic ﬁeld applied to the component changes.
3 In class we derived a vector equation for the force produced on a current element due to the magnetic ﬁeld where it is located. Which of the following was not used in that derivation? Ii! the BiotSavart law
I: B 3 the equation deﬁning the magnetic induction (magnetic ﬁeld) d
. . . 3.:
'1 C:J the deﬁnition of electric current do
. . . d "‘
I: D:] the deﬁnltion of veloc1ty d t A
E E II the speciﬁcation that the length of the current element is a vector in the direction of the current Id 4 What is the equivalent resistance of a series combination of a 6.000. resistor and an 8.000. resistor?
I: A 3 3.43 .0.
E B 2' 0.292 .0.
E C 2' 7.00 l]
Ili 14.0 .0. E E 3 None of the above 5 At time t, the magnitude 30‘) of the uniform magnetic induction perpendicular to the plane containing a ﬂat wire
loop is given by
BU) = 303"”, where B0 and a are positive constants and e is the base of the natural logarithms. If the area inside the loop is A
and the resistance of the wire is R, what is the absolute value i(t) of the current ﬂowing through the wire at time t? QABO _ 8—0!) c B 2 mo] = aABOeWR
: c 2 Ii(r) = aABo (1 —~ eWR) trAB0 _m
R e ‘.‘ E E 3 None of the above EA: i(t) = sup mm = What is the magnitude of the magnetic induction inside an ideal solenoid with 4000 turns per meter if it carries a
current of 3.00 A? I3133' 7.50 X 10‘4 T .9120an )B’IsﬂoIN ‘Wﬁ We
EC1"1.68><10‘3T _ IID: 1.06 X 10‘9 T * None of the above 1%
7 What is the magnitude of the magnetic force on a proton moving with a velocity of 8.00 X 105 m/s perpendicular
to amagnetic ﬁeld of magnitude 0.500 T? .— — 1°!
; : .(9 mo C
IIA:I 4.00X105N ﬂ f{J % l
12 4'  6
.53: 2.56X10 N Eb {Eur} [(51 stJQ— r: 9.0 mo :73
cc: 2.50x1025N / 7 N‘DGBOKIDLB (0.30) ..—
co: 1.00x1025N F5 = Q'Q’ “'0 '_,I_,> [J \BI ‘ 0 SD T
(a
Noneoftheabove Fezé'qxlo a": 90° 8 A very long straight horizontal wire carries a current of 20.0 A toward the north. What are the magnitude and
direction of the magnetic ﬁeld at a position 3.00 m direc above the wire? AP
In! 1.33x106T,east 3 w 3 swam ”
o E N ' r1
:3: 4.19x lOﬁT,east a) .l (a! IL”, 3,0 cc: 1.33x106T,down {lg} '— M = = a ., I am: (a)
:D: 4.19x 1061", down ‘Q’D’ R __ PL
IIE: Noneoftheabove lggxw G) 9 What is the resistance of the ﬁlament of a light bulb if a current of 0.500 A ﬂows through it when a potential
difference of 12.0 V exists across the ﬁlament? :A: 6.00.0. 62:1 ’42; L9: ; DJJOD.
can 4.17x10rzo I 0'5 e 24.00 ED: 3.ooo  — I: E 2' None of the above 1 0 If a current of 3.00 A ﬂows through a 0.200H inductor, what energy is stored in the magnetic ﬁeld created by the inductor? 'L
uni0.9001 le: .L L I
EB: 0.600] 1
cc: 0.0667]  l (or?) (31)
CD31.80J we" a ' E E 3 None of the above SCRATCH SHEET Information you may or may not need: gravitational acceleration near earth = 9.80 mj's2
absolute value of electronic charge = 1.60 X 10‘19 C
rest mass of electron = 9.11 X 10'31 kg rest mass of proton = 1.67 X 10—27 kg permittivity of vacuum = 8.85 X 10‘12 Elm
permeability of vacuum = 42: X 10‘7 T~rnlA speed of light in vacuum = 3.00 X 108 m/s
proportionality constant for Rayleigh criterion for resolution for circular aperture = 1.220
Planck’s constant: 6.63 X 10'34 Js
StefanBoltzmann constant = 5.67 X 10’8 W/(m2K4)
ﬁrst Bohr radius in hydrogen = 5.29 X 10‘“ m
ground state energy in hydrogen = —13.6 eV 1 cutie = 3.7 X 1010 decays/s l/‘IOne taste is equal to a I newton
(EB: am remote—r7 I: C =1 newtonmeterlampere.
E: D‘3 voltlohm.
C: E 3 webet‘lsecbud.
7( 2 In the context of classical electromagnetism we are using in'elass, Faraday’s law (of induction) can be derived from
E A 3 Ampere’s law. I
«2 an the BiotSavart law. ‘
V’ CC: the deﬁnition of the magnetic ﬁeld (magnetic induction).
E: D 2' Coulomb’s law. other laws. because it is itself a separate physical law that must be veriﬁed by experiman 3 Ampere's law states that
E A=I__ the magnetic ﬁeld at a point equals the line integral of the magnetic ﬁeld about a closed curve. C Bi the magnetic ﬁeld at a point due to a current element is proportional to the cross product of the current
element and the unit distance vector to the ﬁeld pennant! inversely proportional to the 'square of the distance. E C: the emf induced about a closed curve equals the negative time rate of change lathe ﬂux enclosed by the r urve. A _
integral of the dot product of the magnetic ﬁeld and the displacement around a closed cm‘ve equals the perniehhility oivacuum multiplied by the current enclosed by the curve. _
'—' E3 the current through across section equals the time rate of ﬂow of charge through the cross section. l/ 4 A V emf battery delivers a current of 5.00 A. What power does the battery'deliver to the current?
@330 C BI! 1.20 W
C C 3 0.833 W
E D: 150 W
C E 3 None of the above x The “qu11” shaped thex—y plane below carries a currentlfromy = no backtoy = no. The Witches
in a magnetic ﬁeld given by B = szj. where C is a positive constant. What is the magnitude of the net magnetic
force on the portion of the wire shown below? 7 ‘ , 2
:A2 F = Icor1 —x,)(x—2§i1) y :3: F=IC(,r,_—xl)(x§'xi)
cc: F=§IC(x2—xl)3 _ . recipe =§IC(x§—xi)
ll: E:I None of the above 7( 6 How much current ﬂows through a coil of wire of inductance 3.00 H if 0.0600 J of energy is stored in its magnetic
ﬁeld? J E E 3 None of the above /7 A wire of length 20.0 m cross section area 3.00 X 10‘6 rn2 hasa resistance from one end to the other of
0.400 .0. What is the resistivity of the material from which the wire is made? ‘ jcaa 3.00m 8  _ Vac: 1.80 x 1013 am
c D: 1.6? x 107 can
'2 E:l None of the above x 8 You are looking northward at a metal picture frame fastened ﬂat against the vertical wall on the north side of a room.
. The frarne has an area of 0.600 mg, and the four sides are of negligible thickness but have a total resistance around
the frame_ of 0.200 .0. A southward horizontal magnetic ﬁeld penetrates the wall. The magnetic ﬁeld decreases
from 5.00 X 10”?“ T to 2.00 ><10‘3 T in 0.400 s. What averagecurrent do you "observe" in the frame during this
process? ‘
EA: 0.0625 A, clockwise
E B:J 0.0625 A, counterclockwise
31/" I; C =1 _ Q‘QZZSAArcloclewisem ,rt"6.::'uD :1 0.0225 A, counterclockwise
3 None of the above A 5110!) resistance, an 8.0041 resistance, and a 6.00V emf battery of negligibleresistance are all connected in =03 0.51315;
WED: 18.5A
CE: None of the above 10 A current of 8.00 A ﬂows through a wire for 2.00 X 101’ s. What charge passes through the cross section of that
wire during that time? CA: 1.28 X 105 C E E: None of the above _ __0.‘f0fl = p ' p. I 20.0»
smxto‘ﬁnt '
. anonfgoomo'mz)
\ W 20.0% . . EB" 6707?
g; = (3x,o’%)@.bm‘) ..
fﬁaoﬁow
, 5: MW]? 0.009ﬂ/
OJIA. aoowv '
I: 0.20.0. = o____.0225 4v PHYS 202 (Sec. 1) TEST 2 October 10, 2006 INSTRUCTIONS
NOTE: YOU LOSE 5 POINTS IF YOU FAIL TO FOLLOW ANY OF THESE INSTRUCTIONS. 1. Answer this test on the furnished SCANTRON card (or its equivalent) using a #2 pencil.
2. In the blank labeled “NAME” on the SCANTRON card, print your name. 3. Read the directions in the box labeled “IMPORTANT” on the SCANTRON card. Note that (a) you must ﬁll
the entire rectangles when coding your ID or an answer, and (b) you must erase pencil marks as completely as
practical when changing your entries. 4. Following the instructions in the box labeled “PART 1” on the SCANT RON card, write your ninedigit Cajun Card number (not your CLID or your Social Security number) in the appropriate ID spaces, starting at the top
row. Code your Cajun Card number by marking through the correct numbers as instructed. The bottom row in the ID box should be left empty. 5. Each question in the attached test has a corresponding row on the SCANTRON labeled by the question num
bers “1”, “2”, etc. Mark through the letter on the SCANTRON card closest to your answer for that question.
“Closest” for scalar answers is the choice whose difference from your answer has the smailest absolute value.
“Closest” for vector answers is the choice whose vector difference from your answer has the smallest magni
tude. You Iose ten points for each question in which you mark no answer, a wrong answer, or more than one HHSWCl'. 6. When you are through, double check your marks and erasures! Also, be certain your answers are in the rows
corresponding to the question numbers on the test. 7. Turn in only the SCANTRON card. 1 The physical law that predicts the magnetic ﬁeld produced by a small element of current is ﬂhe BiotSavart law.
MD Lenz’s law. E C II Faraday's law.
I: D II Snell’s law.
E E 3 Weber’s law.
2 suppose you have a battery with a constant emf and a constant internal resistance. A light bulb is connected to the battery with wires, forming a closed circuit such that the bulb glows. Suppose you now connect a second bulb in
parallel with the ﬁrst bulb. Which of the following happens as a result? E A 3 Less total current ﬂows from the battery. «3911 The total resistance of the circuit increases. c C :I The current through the ﬁrst bulb increases. I"? if #15 C D II The voltage difference across the ﬁrst bulb increases. '   11 each ﬁgure below, the symbol irepresents the current through the resistance, that current being induced by the
change indicated. The direction of the induced current i is correct in only one ﬁgure. Which one? 4..__ ............>
as ‘ Ti current I LR as magnet as magnet decreases [eaves 100p enters loop as switch closes as switch opens sea C
C D :I D
c E‘; 3 E
4 A certain level lawn has an area of 1500 m2. At the location of the lawn, the Earth’s magnetic ﬁeld has a magnitude of 5.00 X 10‘5 T and points downward 60.0“ below horizontal. What is the absolute value of the magnetic flux
thrOugh the lawn? C A..?....37.5_><.__1072 Wb 7 \r " K  _
<;:—ag§.50xio%3wb V/of/gﬂﬂl/gﬂ “50) : éaé KM cc: 0.150Wb : D a 6.67 ><10*8 Wb E E 21 3.85 X10 “"va 5 6 7 8 9 :I 0.267 N, eastward «2440: 2.67 mi"? A 3.00C charge moves with a velocity of 200 m/s eastward in a magnetic ﬁeld. The magnetic ﬁeld is 4. 00 X 10“3 T
toward t orth. What is the magnetic force on the charge? , upward "3
r: c: 0.267 N, westward 3 V 200 V Li W” 1: D :1 1.50 X 105 N, southward 2 tr 4/
E E I! 1.50 X 105 N, northward Mp A certain box contains positive electric charge (10) at time t > 0 given by 40.0 C82
40) = Assuming the usual convention for current ﬂow, i.e., in the direction of positive charge movement, what is the total
electric current through the walls of the box at time t = 5.00 s? are 0.320 A out of the box? 1 E 20 A late the box
K. r: c :1 A out of the box C D II 16.0 A out ofthe box
E E 3 16.0. A into the box A very long copper rod of circular cross section has a radius of 5.00 cm. It carries a current that is uniformly
distributed through its cross section. Consider two points near the center of the rod but located at distances
2.00 cm and 3.00 cm, respectively, from the cylindrical axis of the rod. If the current produces a magnetic ﬁeld of
magnitude 4.00 mT the ﬁrst point, what is the magnitude of the magnetic ﬁeld at the second point? c B a 1.78 mT é () 593 9.003111T r} :f ‘ (if; . 2) I f/
' mT '59] if " HQ “vi:3 .1. {(3 r E: 1.60mT g {— Hg, A light bulb is connected across the terminals of a battery with an emf of 12.0 V and negligible internal resistance.
If the bulb dissipates 3.00 W of power, what is its resistance? ' CA3 36.0.0. , c B n 4.00 n K f V” ‘
cc: 2.000 iiV __ g0.) a?!” ,6’625
994 43.0 07> i .J J c m L13: K c E a 0.250 n In a sample of ordinary iron, there are 8.52 X 1022 atoms per cubic centimeter. The magnitude of the magnetic
dipole moment associated with each iron atom in the sample is 2.10 X 10‘23 Amz. Consider an iron bar magnet
of volume 20.0 cm3 that is sufﬁciently magnetized that all the dipole moments of the atoms can be considered
aligned. What is the magnitude of the total magnetic dipole moment of the magnet? c A :1 4.06 x1045 Am2 : B a 4.93 x 1045 Amz
: C a 8.95 x 10"2 Amz c D a 11.2 Am2 D 2 44214; x (11“?! "' Mir/ﬂ q . “g s .‘ 3?"
)(§’(,r:' l/ ‘1 (J), K} 1 O A metal rod is falling vertically at a certain location on the earth where the earth’s magnetic ﬁeld is 5.00 X 10‘5 T
pointing horizontally to the north. The rod always points in an eastwest direction and has a length of 3.00 m. When
its speed is 20.0 m/s, what is the absolute value of the emf induced across the rod, and which end is positive? , ‘ '— 3”3'.'00 X 10—3 V, west end positive
E C II 3.33 X 10‘4 V, east end positive
C D 3 3.33 X 10‘4 V. west end positive
I: E 3 1.11 X 10‘4 V, east end positive (1' J03 SCRATCH SHEET Information you may or may not need: gravitational acceleration near earth = 9.80 mils2
absolute value of electronic charge a 1.60 X 10‘'9 C
rest mass of electron = 9.11 X 10‘31 kg rest mass of proton = 1.67 X 10‘2“r kg permittivity of vacuum = 8.85 X 10‘12 F/m
permeability of vacuum = 4n X 10—7r Tm/A speed of light in vacuum 2 3.00 X 103 m/s
proportionality constant for Rayleigh criterion for resolution for circular aperture = 1.220
Planck’s constant = 6.63 X 10‘34 J s
StefanBoltzmann constant 2 5.67 X 10“8 W/(m2K4)
ﬁrst Bohr radius in hydrogen = 5.29 X 10'“ m
ground state energy in hydrogen = —13.6 eV 1 curie = 3.7 X 1010 decays/s ...
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 Spring '09
 JOHNMERIWEATHER
 Physics, Magnetic Field, Scantron, scantron card

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