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Unformatted text preview: COM ED4 11. P
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EM Physics 102 FORM 0 ED4 11. COM [l] Two charges, Qi and Q 2 ) are separated by a certain distance R. If the magnitudes of
the charges are doubled, and their separation is also doubled, then what happens to the
electrical force between these charges?
it remains the same
[B] It is doubled
[C] It is halved
It is quadrupled
[E] It decreases by a factor of 4
11. COM  PR
EM t ED4 11. COM  PR
EM ED4 [2] The electric potential at x = 2.00 m is +400 V, and at z = 10.0 m is 2000 V. What is
the magnitude and direction of the electric field?
[A] 200 V/m in the z direction
([B))300 V/m in the +x direction
[C] 400 V/m in the +x direction
[D] 600 V/m in the z direction
[E] 800 V/m in the +x direction
 PR
EM i ED4 11. COM [3] The potential difference between the plates of a parallel plate capacitor is 40 V, and the
electric field between the plates has a s trength of 800 V /m. If the plate area is 0.020 m 2 ,
what is the capacitance of this capacitor?
[A] 5.7 x 10~14 F
[B] 5.3 x 1Q13 F
/[CJ)3.5 x 10~12 F
[D] 9.1 x lO"11 F
 PR
EM [E] 2.1 x 109 F ^^  PR
EM ED4 11. COM [4] The length of a certain wire is doubled while the radius is halved. What is the change in
the resistance of this wire?
[A] It stays the same.
[B] It is reduced by a f actor of 2.
It is increased by a f actor of 4.
[D] It is reduced by a factor of 6.
It is increased by a f actor of 8.
11. COM §  PR
EM ED4 [5] A 5.0 /zF capacitor is connected in series with a 3.0 kfl resistor across a 20V DC source
and an open switch. If the switch is closed at t = 0.0 s, what is the charge on the capacitor
at t = 12 ms?
0C
[B] 37% of the maximum charge
[C] 45% of the maximum charge
55% of the maximum charge
[E] 67% of the maximum charge
MPRE
M ED4 11. COM § MPRE MED 411 .CO [6] A policeman pulls you over for running a red (A = 700 nm) light. You claim before the
judge t hat, before you s topped, the light appeared green (A = 550 nm). How fast would
you need to be moving toward the light for this to be true? Assume that the nonrelativistic
expression on the formulae sheet is still valid.
[A] 0.12c
fli])0.27c
[C] 0.39c
[D] 0.52c
[E] 0.78c PRE MED 411 .CO MPRE MED 411 .CO MPRE MED 411 .CO MPRE MED 411 .CO [7] Arrange the following forms of electromagnetic radiation in order of I NCREASING energy
_per photon.
([A} radio, microwaves, infrared, visible, xrays, gamma rays
[B] radio, microwaves, infrared, visible, g amma rays, xrays
[C] microwaves, radio, infrared, visible, xrays, g amma rays
[D] radio, microwaves, visible, infrared, xrays, gamma rays
[E] gamma rays, xrays, visible, infrared, radio, microwaves OM D41 1.C P
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EME Physics 102 FORM 0  PR
EME D41 1.C OM [8] If you separately measure Erms and Biras of an electromagnetic wave, how can these two
quantities be combined to form a q uantity that is proportional to the average intensity?
[A] ETjas/Btms
[B] £rms + Bims
[C] (JSnnB™,)1/2
(S) EimsBims
OM \2 D41 1.C OM  PR
EME D41 1.C [9] If the object distance (£)) equals the image distance, and if t hey are b oth in front of a
particular spherical mirror, what is its radius, is the mirror convex or concave, and is the
image upright or inverted?
[A] 2/13, convex, upright
[B] D/2, convex, upright
[C]  D/2, concave, inverted
[D] D, concave, upright
(EpZ), concave, inverted  PR
EME
D4 11. COM  PR
EME [10] In water, a red light (A = 656 nm) has an index of refraction of 1.331, a green light
(A = 486 nm) has an index of refraction of 1.337, and a blue light (A = 397 nm) has an
index of refraction of 1.344. Imagine shining each of these lights from the b ottom of a pool
at some angle 9 from the vertical. Which of the following angles results in total internal
reflection for two of the three lights?
„_
[A] 48.00°
[B] 48.20°
[C] 48.40°
f[D])48.600
[E] 48.80°  PR
EME
D4 11. COM [11] At what angle above the horizon would the sun have to be such t hat the rays that reflect
off the ocean water (n=1.33) are maximally blocked by polarized sunglasses?
[B] 41°
[C] 45°
[D] 49°
[E] 53°  PR
EM ED4 11. COM [12] A heliumneon laser (A = 633 nm) illuminates a pair of slits with a separation of
4.0 X 10~5 m. What is the angle to the third dark fringe above the central bright fringe?
[A] 0.5°
[B] 0.9°
[C] 1.4° @)2.3°
[E] 2.8°  PR
EM ED4 11. COM [13] Sometimes the glass (n = 1.5) in eyeglasses is coated with an antireflection coating
(n = 1.3) t hat produces destructive interference between the waves reflecting from the
glass and the waves reflecting from the antireflection coating. What is the thickness of this
layer such t hat yellow light (500 nm) at normal incidence is not reflected.
[A] 83 nm
@)96 nm
[C] 125 nm
[D] 192 nm
[E] 250 nm 11. COM  PR
EM ED4 11. COM [14] A particle initially at rest splits into two particles. The first particle has a mass mi and
travels at a speed of u j = c /2. The second particle has a mass 7712 = rai/2. What is the
speed of the second particle?
[A] (S/?)1/^
( Ji)(4/7) 1 / 2 c
[C] ( 3/4) 1 / 2 c
[D] the reaction is not allowed
[E] not enough information is given
 PR
EM ED4 [15] The kinetic energy of a particle is equal to twice its rest energy. What is the particle's
velocity? [B] (l/S)1/^ COM [A] ( l/Q) 1 /^ [C] (l/2}l/2c [D] (3/4Y/2c PRE MED 411 .CO MPRE
M ED4 11. COM  PR
EM ED4 11. [16] In a hydrogen atom, the electron makes a transition from the n — 8 to the n = 3 state.
What is the wavelength of the emitted photon?
[A] 3.1 x 10~Y m
@9.6 x 10~7 m
[C] 1.1 x 10~6 m
[D] 3.3 x 10~6 m
6
[E] 4.5 X 10' m OM D41 1.C P
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EME Physics 102 FORM 0 OM  PR
EME D41 1.C OM [17] An electron in a hydrogen atom is described by the quantum numbers: n = 8 and mt — 4.
What are the possible values for the orbital quantum numbers tl
[A] only 0 or 4
[B] only 4 or 7
[C] only 5 or 8
/[5) only 4, 5, 6 or 7
[E] only 5, 6, 7 or 8 OM  PR
EME D41 1.C [18] Which one of the following is the correct ground state electronic configuration of the
magnesium atom (Z = 12)?
[A] Is22s22p2
[B] I s 2 2s 2 2p 6
f [cjls 2 2.s 2 2p 6 3s 2
[D] Is22s22P63s23p2
22
62
6
[E] Is 2s 2p 3s 3p
^  PR
EME D41 1.C [19] A nucleus with a diameter of 7.2 fm has a mass number of
[A] 3
[B] 6
rfc)27
[D] 133
[E] 216 PRE MED 411 .CO MPRE
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EME
D4 11. COM [20] Carbon14 has a halflife of 5730 years. A sample of wood has been recovered by an
archaeologist. The sample is sent to a laboratory, where it is determined that the activity
of the sample is 0.167 Bq/g. By comparing this activity with the activity of living organic
matter, 0.230 Bq/g, the scientist determines how old the wood sample is, or more precisely,
when the tree t hat the sample came from died. How old is the sample of wood?
JA)2650 years
[B] 3870 years
[C] 4250 years
[D] 4590 years
5730 years OM D41 1.C P
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EME Physics 102 FORM 0 PRE MED 411 .CO MPRE
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EME D41 1.C OM [21] Consider the long, straight, currentcarrying wires shown in the figure. One wire carries
current Ii = 8.0 A in the positive x direction, and the other wire carries current /2 — 4.0 A
in the positive y direction. Points A and B are at distances d = 16 cm from the two wires,
as shown in the figure. Let z be a unit vector pointing in the positive z direction, thus out
of the plane shown in the figure.
(a) Calculate the contributions B^/i) and B B(/I) of the current Jj to the magnetic field
vector at points A and 5, respectively.
(b) Calculate the contributions B^J^) and B B^) of the current I2 to the magnetic field
vector at points A and B, respectively.
(c) Calculate the net magnetic field vectors B^ and B# at points A and I?, respectively.
(d) How will your results in (a) and (c) change if the direction of the current Ij is reversed? 16 on B OM D41 1.C P FORM 0  PR
EME Physics 102 OM  PR
EME D41 1.C OM  PR
EME D41 1.C OM [22] A copper wire of length 1.0 meter has a cross sectional area of 1.0 mm2 and a resistivity
of 1.68 x 10~8 firn. The wire is formed into a circular loop and the loop is placed into a
2.0 T magnetic field t hat is perpendicular to the area of the loop.
(a) If the orientation of the loop with respect to the magnetic field is changed from
perpendicular to parallel in 2.0 seconds, find the magnitude of the average induced emf.
(b) Determine the average induced current.
(c) What is the corresponding dissipated power? D41 1.C .
An l.O'T. (a)  PR
EME 1 JM c~ II / J7 <*wjV " __ / . 10 .J.M'\,V /
:  •^ „ ED4
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EM
COM 0>)I = ? L A 1 \ ™"» 11. 1=4 411 .CO MPRE
M ED4 11. COM  PR
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EM ED4 ~" MED — If 11. >v. PRE ~ COM f.  PR
EME
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EME
D4 11. COM }0 u> = 03? OM  PR
EME D41 1.C P
FORMO 1.C OM Physics 102  PR
EME
D4 11. COM  PR
EME D41 1.C OM  PR
EME D41 1.C OM  PR
EME D41 [23] Compute the energy (in Joules!) of the photon in each of the following cases:
(a) the photon emitted at the peak frequency of a 20,000 K blackbody;
(b) the photon that strikes an aluminum target (with a work function of 4.28 eV) and produces
a photoelectron with maximal kinetic energy of 9.0 eV;
(c) the photon that Compton scatters off an electron at an angle of 120° with respect to the
incident photon when the incident photon has a frequency of 4.6 X 1018 Hz;
(d) the photon produced as a result of the annihilation of an electron and a positron; assume
the electron and positron are initially at rest, and that two photons are produced in the
annihilation process. t w. > PRE MED 411 .CO MPRE
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r^ f OM 1.C P FORM 0  PR
EME D41 Physics 102 OM  PR
EME D41 1.C OM  PR
EME D41 1.C OM [24] A typical fission reaction in a nuclear plant is:
+J n
Ba
Kr + x \n + Q,
where the atomic masses are: m^l^U] = 235.043925 u, m^fjBa) = 140.914406 u,
m(jKr) — 91.926153 u, r n(Jn) = 1.008665 u, and z is some number of neutrons.
(a) F indz.
(b) Calculate the energy produced, Q, in MeV units.
(c) Calculate the mass (in kg units) of 2f U consumed each year by a 50.0 Megawatts power
plant operating (on the basis of the above reaction) at 50% efficiency of conversion of heat
to electricity (1 yr = 3.15 X 107 sec). = 11. COM o  PR
EME D41 1.C ToVU PRE MED 411 .CO MPRE
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EME
D4 (i**«xc v l oV •*• =• 3 OM D41 1.C P FORM 0  PR
EME Physics 102  PR
EME D41 1.C OM FORMULAE SHEET I 1.C OM e = 1.60 x Kr19<7, me = 9.11 x KT31^ = 0.511MeF/c2, k = 8.99 x lQgNm*/C*
lkWh = 3.6 x 106J, e0 = — = 8.85 x W12C2/Nm2 D41 leV = 1.60 x 1(T19 J, COM vVa 1
v n  T=
yfi J ~""' 11. Q FFnc = AJf + AC7,  ~ "" ~ = 7 r UE = ' F=— "' ' "  PR
EME
D4 11. COM T' A F = EAs,  PR
EME PFE  goEd = g0AF, go  PR
EME
D4 V = —, D41 1.C OM  PR
EME 47TK 2 ED4 mv = qvB, F = HBsmQ, (long)'  PR
EM ED4 11. COM  PR
EM qvBsind, ^'P, £ = "
COM (T
'
^/^O 11. ED4  w <),  T r /J,0 = 4?r x 10~7 27rd £ = vBt, ' (coil) £ = NABusinut, ' A T• ''p :== k = ^, Tm (solenoid)
u = 2Tr/ = ^
_/. T/~ = ~ r~»
'p
's E = cB, _ 5r
J? L
== r nis'rms? I
J'
•'rms = ^ =>
V2 _L
R
' rms c  —= = 3.00 x 108m/s, =: ^F
\ /2 A/=c PRE MED 411 .CO MPRE
M ED4 11. COM  PR
EM ED4 11. COM  PR
EM O sin(^z: ^ —r v  / • n r = NIABsin@, AJ
Af' 11.
== i .At ED4 ^B  PR
EM ' COM ~~n
Z I = —,<~~r v / • n
K. 11. COM q = C£[l  exp (t/r)}, 2
2 / OM D41 1.C P FORM 0  PR
EME Physics 102 f di
2 h0 „ t an #„ = — ,
TIL
 PR
EME sin PC = — i
ni ^vac n
V——
f — = 7 + 7 ,
f
h
h d sin0 = (m + 1 /2)A, m = 0 , l , 2 . . . ,
(double slit, dark)  PR
EME D41 1.C OM , m = 0, 1,2 . . . ,
(double slit, grating, bright) , n d0
2 D41 sin P! = ra2 sin 02 j c 1.C OM d0  PR
EME D41 1.C OM FORMULAE SHEET II (resolution) 11. COM (single slit, dark) Afp / bright \
Uark J  PR
EME
D4 n 1 <n<n 2 or nl>n>n2\
m < n > n 2 or m > n < n 2 J /—^ ^a6 + f fee  vac = —— y/l'U2/C2 , ? / ?  PR
EME
D4 11. COM v*t? /dark ^
V brightJ , .  o , COM y 1 — f 2 /c 2
11. /i  6.626 x 1(T34 J 5 = 4.135 x l(T15ey 3 = 1240eV nm ED4 c 27T  PR
EM Xl\ = \c(icosB), ATmax = ^ /  W 0 ,
Ac = — = 2.426 pm,
m.ec E = / i/
AdB = p  PR
EM ED4 11. hf = hf' + K, , n = — = 1.054 x 10~34 J 5 C ^ = 5.88 x lO10*"1^"1, COM A p r  2.898 x 1 0 3 m#,
p =  = ^,
c
A 0 COM K=— , 2 dsin^ = m A, A p z Ax > , AEAi > , r  273.15 K = Tc = ^(Tp  32°)
2m
2
2
9
h2
Z2
ke2
a0 = —  = 0.0529 nm, En = E0 — , E0 = — = 13.6 eV  PR
EM ED4 11. nft
n2
rn=  = ao^r,
mevn
Z  a = 0 ,1,. . . , n  1; m/ = 0 ,±1,...,±^; ms  ±  11. COM  PR
EM ED4 11. COM 2 PRE MED 411 .CO MPRE
M ED4 11. COM Ai  PR
EM ED4 , 1 « = 1.6605 x 10~27fcs = 931.5 MeV/c2, = XN, N = N0exp(Xt), X= Ti2 , f= X NA = 6.022 x l n , 1 Ci = 3.70 x
R ...
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 Fall '08
 Ashkenkai
 Physics, Charge, Force

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