PHYS 305 Final
American University of Beirut · Quantum Mechanics · 6 pages
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‘Phys 305
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Final Exam .. Fune 1995
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Nei homes 3 heurs
I. Shot Questions. ( please shect answers )
Qi. xf the onsrgy argon ualials H an obsecvahle form a ce
qwatiauwous spectum, how <5 Lt possible be form &
physically alceptable stake 2, Explah De term "phys cuably
Qa. Lf lx) ds an Lrirgy Ligon funchon of an observuble
and t5 a stahonary slate » In which way <t becomes
Lemme — dapendoat 2
Q3. A spn-t parhcle xs plaad mwa consdand magnthe
fab aleng He Z-axis. What is the pared bf
Yolahen of Hu sp as dima Progaass 2, Can this
folahen be cliscy ibec in quantum midanits aS
pracessing ahoat As @-ans ? rf ned why 2
Oe. What vs +s uncertamty ridahen [A x), (A Ph
dora harmenic Oscitladoc cn thy shale In> 2.
Guive dt Vala for PSE Ground shu le ln=o0> . ‘Expdun
the pry sicak moaning of the fact Phat (Ax), (Ap), do.
Hint . Y ou netd a short calculahon sf (Ax)? aud
2 in
(AP), by using dAs opvadar a and at.
(5. Tha entegy tiyeafanchons of ths raclial Wave £4oalion
wre 21, 0,b1E4m> = Ble) Vim (G4) What
As ths phys reason for this separahor d/ween
thy yada and angular Pard 2
Afi ineag eee
“CAN UNte nner
[ MRR Ap Y
OE pray
ee
PAYS Boy
Final Exam Tune (995
Tl. Problems
There are 5 Problems, The Problems @, @) and G)
are obligatory » You can chouse between problem
@® er ©
Yr. Hy drogen Actonn,
Given «> the wave functien 4
-/2
ps bh) ee Og
Y (4 oe) = “Fr e. 1 (GP),
where Ag= une he AS ths Bohr Tadurs and
A As a Constant °
(a) Solve t+AL dima —aurclep endlont Sthrddinger 4 4uahon
do show that W (7 &) AS an Lye function BY AL”
alichun av tha hy drogas atom ) f ads spin dgrat
o} druacdom AS net cons derad -
(b) WAad are dha cecresponding enlcgy Lig valuts ?
) Which quantum numbers CN, bm) chavadtriee
Hy she of He elechon 2
(C
Phys 305
eam Tune 1995
712. A spin 4 Parhele as at dime t=0 wm the
wo fA Z> Stile. L's plaud wa skong magnthe
| diskd Bea (0,0, Bo) and aman Oseillahng fiald
= = >
B _ B, cos wt x? B, snwt qd °
(a) Show that da Hansihon Probabitity dy thy
1-ZS shle at # Ame t ds VK by
0
W_ = Us Ba su CA -t),
4 Bn 2 2 247k
Where A 4 Ue Bes) +B, ws 1
Y ow assume only spn grt df brezdonn for
the Pardele , that as Be Hamitlonian &s giver
by : =>
J H=—-ts SB
(b) Distuss the yasuGt oblaiwd for Ais so calle
U
" Paramayne hc Fesorang absorphon -
H mt, Af Construching +a Hamillonian , Ae basic
ASSUL ay dav. do (low Ad, kvokuhon J thy
vee =( 38)
This Problem a5 relahvely long }
Final Exam Tune (999
Ds. The spin Hami Glonian f a spin—~t Parkclt
fb as givta as cn Problem (L.A). However, the parhile
| ds placed in an wernal magrahec field :
B= (0, By, Bo),
whore By >> Bg -
(4) First, didecming He onirgy bigenvaluts biaclly , |
(>) Then , cateulale inthe frambmork cal Pydurbadion
tree ds Sntrgy bxgenrvalits though second ordt-
An B2 [Bo , and. compare ths vasulls ant He
Axect values tn prt (a). Do you pnd agreemtyt ?
Llints -
rn part (a), ducing Your dip adfink
tly = = fs By and 4, = - Ms By
Tn Part (b) > Your trip as not Doing Ay tad
before second —ocdy begy shift.
Tu. A molecule rotates rigid ty wa Sspag about
af the origin ef the Covcdinale Syskim anth two
dtara of frtdom disertbed by the Polar args
re) and cf ° The Ham tontan a's pve by
LI = pr ) Tez mMemént of nicha
AT :
(a) Find He Ut veluts and Lagoa func tien and
thir possible digentracy _
(b) At 4 given Aime , the rodator As tn the shake
W(Gp) = al coe + SiMe Cos2d)
white oo és & normali2ahon conshint (stad 2
r4 12 As mgasuced what ts HAs peobabibihy
of dindwagy Hye values :
ode and © (ao) %
(c) rf A SemuLtangous measurmint of 1°
und tg is dent, What ts He probab, Gly.
od. finding thy vabuts (€h",- 2h)?
Llint. Fake a Fook at Hs sphniwd harmenice
on Page QC€ cn te book .
Dane 1495
Ts. Co ld Emissiav Ham medals
ao TH is bprimintally known that an applud shang
tlichic hud necmuf Ad Hy surfacé of a medal
Atals 4% Dmission Carrlrd oud sels the metal. The
Liphanahon 64 this Cold emission effect " As Possible
biy the dannel effect . Aceesdiny +r Ha Paubj Principle ,
the as conduchon ehucdons occupy at 24¢e dem prraha rie
(T= o) Dy fonduchon band Up At PL Ferm — Engg.
Ef ( see fegure). The work fancdon A's defined as
Wea=Vo- Ep .
The effect of thy acdynat Field is As change the
Polnh al Ve dd VOL) =Ve-CEX us shown
ch tl de gu reo
4 ts reasonable to assume that the elecdune
nar the Perm —sacface leave the mutel , sinte
the Lunnel clishnu ts As shorkst .
Ca Peutale thy emission Curréut >
| €=€)
as a danchov al Wo and E, and Jo ‘
a
Hint - see Equahion (6. (59) as a shavhng Point