Spring Physics 240 2001 FinalExam 1. Twoparticles,X and Y, are4 m apart.Xhasacharge otzQand Y hasachargeof Q.Theratio of the magnitudeof the electrostaticforce on X to that on Y is:
A) 4:1 B) 2:I 9) 1:1 E) L:4
Ns^,\o1'1 Low J,-A
D\ r:2
force on the positive chargeis: The electrostatic 2. A 5.0-C chargeis 10 m from a -2.0-C charge.
charge \=-___% AL9.0x 108N towardthenegative x
B) 9.0 .l0sN awafFffiffi n'6EiiiVilcharge N the charge c) 9.0x 10e toward negative D) 9.0 x 109N away from the negativecharge E) none of these
f. 4,1,
*.t
trtd,fr -
concerning electricfield lines: 3. Choosethe correctstatement
A) fie*d#nos'ma*ereso B) field linesareclose
c)
where field is laree the Jine,
D) a.goi. E) noneof these correct are
Page I
Physics240 Spring 2001 Final Exam
4. The diagram shows the electric field lines in a region of spacecontaining two small charged (Y spheres and Z).Then:
/
I I L I
\
I
+f
\tjY+\)4tlx y4l--+-(
/ r h - i , \
t
*3*
l
/.)---a1t
u l xv/o ' r t
- . / r \ \ \
+
\
.
}I B\ C) p) -q
Y is negative andZis positive the magnitude theelectricfield is the same of everywhere theelectric field is strongest midway between andZ Y a smallnegatively charged bodyplaced X wouldbe pushed the right at to V andZmusthavethesame sign
5. A point charge placedat thecenter a spherical is of Gaussian surface. electricflux OB is The changed if:
xJ
cI
the sphere replaced a cubeof the same is by volume
is B) thesphere replaced a cubeof one-tenth volume by the thepoint charge movedoff center(but still insidetheoriginalsphere) is pointcharge moved just outside sphere D) the is to the pointcharge placedjust a second is outside sphere the EI 6. Charge distributed is uniformlyalonga long straight wire. The electricfield2 cm from the wire is 20 N/C. The electricfield 4 cm from thewire is: A) 120N/C B) 80 N/C
c) 40N/c _D)r0 N/c E) s N/C
Page2
l^J. V 1
Physics Spring20Ol FinalExam 240
$1.
from onepoint to another, potential the If 500J of work arerequired carrya 40-Ccharge to pointsis: between these two difference
/
A) l2.sv B) 20,000 v v c) 0.08
D) dependson the path E) none of these
N*b(yoo:&8v
c'$qcu
$t-v*:
!'ttl bL'U
flzu'
f
of movethrougha potentialdifference 1.0x 108V 30 S. During a lightningdischarge, C of charge bolt is: released thislightning by in 2.0 x IF s. Theenergy A) B) C) D) E) 1 .5x 1 0 1 J 1 3J9x10qJ. J 6.0x 107 3.3x 106 J 1s00 J
S * s u * , k q u #f' & ' : T V v
' '\Fs)(tor)[' J Qv
\^l'-tV '
a of: with 2 C requires potentialdifference 9. To charge l-F capacitor a
A) 2 V B) 0 . 2 v
c) 5 V
c.-9 u = 8 , + " J v
v D) 0.5 E) none of these
is in and capacitor connected series a potentialdifference appliedacross are 10. Az-rd. anda 1-,aF I has: rrqD' The the combination. 2-1tscapacitor )
Q t",,4att,o,d Q Eu {erng
of A) twice the charge the l-pF capacitor
of B) halfthecharge thel-pFcapaciror
of C) twice thepotentialdifference the l-prFcapacitor of D) lulljhr- potentialdifference thef1S capacitor
I ' fli r l-' ;n '
CJ'nt t'bf
E) iloGof theabove
lJ , g C
V=Q ,tn{
U ,g
Jur v.j ft\l
fr
Page 3
r/.Av
Physics Spring2001FinalExam 240
1.1. Currentis a measure of: A) B) C) D) E)
4-.+9 + & t
fo\c.e movesa ch\e pasta point that resi5tqnce the molcmentof a clilngepasta point to enblgyused movea cthsgepasta point to pasta point per unit ting* amount qlrarge moves of that pasta point sp{ with which a ch\Se moves
12. If thepotentialdifference across resistor doubled: a is
A) only the cuqgptis doubled B) only the currentis halved
U.:T'R' '
lV = lA,At. f,,(l 4r--(,
is c) onlytheresistance doubled
D) only theresistance halved is E) boththe currentandresistance doubled are
t* Zr,
13. Resistances 2.0Q, 4.0 Sl, and6.0Q anda24-Y emf device all in series. potential of are The across 2.0-Qresistor the is: difference
%
A) 4V B) 8V
c) 12V D) 24V E) 48V
}-rt
{- 2!v
V:tft
4 -.V
$*.[}-
Q"I'llJl
IL
V:)r trlI
1tl V
r* : &[ \a
Page4
Physics Spring2001Final Exam 240
14. Thecurrent the5.0-0 resistor thecircuitshown in in is:
v-. f1
rl,v
^*
9-ru
il.1R
t.Y;lb
1rl
a) 0.42A B) 0.67A C --- ) 1 . 5 A
, lIR
w
(
i';r' a,
4 ' =4
It' l,\n 'It
r
l-.L
'.
D) 2.4A E) 3.0A
r ( 6 Y ^ .i J , 3 a ' t s
JoI, ,}. LI
= (charge -1.6 x 10-19 is movingat 3 x 10sm/sin thepositive direction. An electron C) x A magnetic field of 0.8T is in thepositive direction. magnetic The forceon theelectron e is:
A) 0
B) {;_![l1N in thepositive direction z C ) t r . 1 0 -fi N i n th e n e g a ti ve edir ection D) 4 x 1-0':r4-N thepositive,v in Srection
[-, qrf *8 'r
( t.L"W ") ( 3r r O5) ( ,8) 1. .
1
I /T 7
Y
ni a x 10-14 inthe N "jtrli1g,11direction
f-+
OALA __)
16. An electron a protonarebothinitially movingwith the same and speed in the same and direction at 90oto the same uniformmagnetic field. Theyexperience magnetic forces,which areinitially:
A) identical B)
c) in the samedirection and differing in
by a factorof 1840
D) in opposite directions differingin magnitude a factorof 1840 and by perpendicular eachother E) equalin magnitude but to
Page5
Physics Spring2001FinalExam 240
I parallelwirescrossthex axis andcarrycurrents and3Iin current-carrying 17. Two long straight fieldzero? At the same direction,asshown. whatvalueof x is the net magnetic
ter
A)0 B)1
f\att"L
' -hi-/
&fr r
93, D)s
E)7
{ u 5.
r
(with radii20 mm and30 mm respectively) current. The carrythe same 18. Two long idealsolenoids that insidethelarger,alonga commonaxis.It is observed thereis is mounted smallersolenoid musthaveX timesas Therefore innersolenoid the field within the innersolenoid. zeromagnetic per lengthasthe outersolenoid, whereX is: manyturns
L) 4t9 B) 2t3
&"'/,'\5
c)1
D) 3t2 E) et4
Page6
I
FinalExam Physics Spring 240 2001 , 19. A changingmagneticfield piercesthe interior of a circuit containing three identical resistors. 6 Two vo'itmetersare connectedto the samepoints, as shown. V1 reads 1 mV. V2 reads:
7a r_o-l
*t*
Te,*md L4nLJ
I
I
n*-t^f n
\
A)0 B) 1/3mV C) ll2 mY D) lmV E) 2mV
r-F
fln{"' Le +tIrL
' f,$K
current i rails.To makeaninduced 20. Thefigureshows barmovingto therighton two conducting a 'k a masnetic field in resionA should in whatdirection? be in thedirection indicated. constant
A) Right B) LEft
possible, field magnetic cannot donewith a constant be
s
"+
PageT
@t
Physics 240
21. Spring2001FinalExam MagneticdipoleX is fixed
e Y will initiallv:
A) move toward X but not B) move away from X but not rotate
c) move toward X and rotate
D) move away from X and rotate E) rotate but not translate
n Displacement thereis: currentexistswherever A) B) C) D) E) a magnetic field movingcharge field a changing magnetic an electricfield a changing electricfield
l00Hzusinganinductanceof H.Wealso 2.5 23. Wedesiretomake anLCcircuitthatoscillatesat needa capacitance of: A) lF B) lmF
l h ) -
v
l
I
c)!g
D) 100 lF E) lpF
iltzLL
L J nC r ' I *
I '/ ;t m 1
' - ,I o t
{'f r }p{
capacitor connected a 400-Hzgenerator to is: 24. Thereactance ohmsof a 35-ptF in
A)0 B) 0.014 c) 0.088 D) 11 E) 71
\z
^,
rI
.
;t
'
r.c{ c {lc uco'Jnq-L)
n
l
\.
*
l
.\
1 l\
Page 8
Physics Spring2001FinalExam 240
25. Which of the following is NOT truefor electromagnetic waves?
{ L } they consist of changingelectric and magneticfields f B I they travel at different speedsin vacuum, dependingon their frequency t .)- they transportenergy "Tb) they transportmomentum 'T E\ they can be reflected
in wavein vacuum, ratio EIB of the amplitudes SI unitsof the two the W 26. In a planeelectromagnetic ' fieldsis:
A) the speed light of functionof frequency B) an increasing
functionof frequency c) a decreasing D) J'
'{rw
V. Ve t '&
B
!'xB
t%
E)
lJ,
v , fr
8'-
n
27. Whenyou standin front of a planemirror,yourimageis:
A) B) C) D) E) real,erect,andsmallerthanyou re-al, erect,andthe same sizeasyou virtqal,qregt, smaller and thanyou sizeasvou virtual.erect.andthe same qeal, invbrted, the same and sizeasyou
ffi &ffi@ri+.--
28. A concave spherical mirror hasa focallengthof 12cm. If an objectis placed6 cm in front of it
position is: theimage
A) B) C) D) E)
4 cm behindthe mirror 4 cm in front of the mirror 12 cm behi$,9,,thepinor 12cm in front of the mirror at infinity
. at I
l i I j
I
( 5' f L,L'! ( r' ta
-LvL -l-
. L ,L - L { , } 6
Pase 9 -
L-*'
6{t$ #rL\
r. ra . , '. lr Lvt 6fril t I
Physics Spring2001FinalExam 240
29, Thereason is: therearetwo slits,ratherthanone,in a Young's experiment A) to increase intensity the B) oneslit is for frequency, otherfor wavelength the I to createa pat! lengthdifference D' oneslit is for-Efields,theotheris for.F fields E) two slits in paralleloffer lessresistance
30. Binoculars microscopes frequently and madewith "coated optics"by addinga thin layerof are transparent materialto the lenssurface shown. as Onewants:
incident light 1z
A) B) C) D) E)
interference I constructive between and2 thecoatingto be moretransparent thelens than destructive interference between and4 3 to the speed light in thecoating be lessthanthatin thelens of destructive interference between and2 I
31. Therainbowseen aftera rain shower caused is bv: A) diffraction B) interference
9)-reftaclrg
D) polarization E) absorption
Page10
Physics Spring 240 2001 FinalExam
32. A parallel beam of monochromaticlight is incident on a slit of width 2 cm. The light passing
throughthe slit falls on a screen2maway. As the slit width is decreased: A) B) C) D) E) the width of the pattern on the screencontinuouslydecreases the width of the pattern on the screenat first decreases then increases but the width of the pattern on the screenincreases and then decreases the width of the pattern on the screenremainsthe same the pattern on the screenchangescolor going from red to blue
{
33. A planewave with a wavelengthof 500 nm is incidentnormally on a singleslit with a width of
m. Consider wavesthat reach a point on a far-away screensuch that rays from the slit 5.0 x lf make an angle of 1.0owith the normal. The difference in phasefor waves from the top and bottom of the slit is: 6,1^ c-t 5rt(r I
A) 0 B) 0.55rad
c) 1.1rad
D) 1.6rad E) 2.2 rad
r
I
$^ O. ":f
A,
T,
, r S . * ,. o l:- f 1 Xj3* r*a) ,)," ' a rtrl tro \Y6
1e-9
theory relativity of is: of 34. A basicpostulate Einstein's movingclocksrun moreslowlythanwhentheyareat rest thanwhentheyareat rest movingrodsareshorter light hasboth waveandparticleproperties observers movingwith uniformvelocityrelativeto mustbe the s4mg,fgr tbg.gy: of phy.sics eachofher is ielative E) ;;tyilng A) B) C) D)
is: of theory relativity of 35. A consequence Einstein's A) -BI C) D) movingclocksrun fasterthanwhentheyareat rest thanwhentheyareat rest movingrodsareshorter light hasboth waveandparticleproperties the to mustappear same all observers movingwith uniform velocity thelawsof physics relativeto eachother is E) everything relative
Page1l
Physics Spring 240 2001 FinalExam 36. The proper time betweentwo eventsis measured clocks at rest in a referenceframe in which by the two events:
A) occurat the same time B) occurat the same coordinates D) occurin Ann Arbor E) satisfvnoneof the above
c) areseparated the distance light signalcantravelduringthe time interval by a
37. Spaceship traveling pastus at 0.7c,sends message A, a capsule spaceship whichis in front to B, of A andis travelingin the same directionasA at 0.8crelativeto us. The capsule travelsat 0.95crelativeto us. A clockthatmeasures propertime between sending receiving the the and of thecapsule travels: A) B) C) D) E) in thesame direction thespaceships as at0.7crelative us to in theopposite direction from thespaceships at0.7c relative us to in thesame direction thespaceships 0.8crelative us as at to in thesame direction thespaceships 0.95c as at relative us to in theopposite direction from thespaceships 0.95c at relative us to
38. A rocket traveling with constant velocity makes 8.4x 1015 ffip in I year.The propertime in a m years between events whichmarkthebeginning endof thetrip is: and
lPa* l)"'+a-
ffi
A) B)
0.21 0.46
rF tvl :
I
6o *,19* -15!nltH?*'nl^ irr d""V \f
j , t151 tt 6
U. l.[6r gP
\.'r'
1r-"-
l-uzr
39. A meterstick movesat 0.95cin thedirectionof its lengththrougha laboratory. Accordingto
measurements takenin thelaboratory, lengthis: its
\
-lrrcB) 0.098 m C) 0.31 m ffi*-rr P).-J-Q.II}
bL,ab 1
sI
Page12
Physics240 Spring 2001 Final Exam
40. Quasar is movingawayfrom us at a speed 0.8c.Quasar is movingawayfrom usin the of Q2 Ql on by opposite direction a speed 0.5c.Thespeed Ql asmeasured anobserver Q2 is: at of of A)-&*lc
Er-ftsc
C) 0.93c TfmSe tH'fZc
Page 13