www.physicskerala.blogspot.com 2o12
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UGC CSIR NET 2012 December 23 Answer Key Comment here with explanation
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partc:uncertainity in momentum question:ans was square root h/2mw....is it correct?
ReplyDeletePLEASE SHARE QN PAPER
DeleteThis comment has been removed by the author.
DeleteIt is definitely squre root of h/2mw
Deleteright. there is a square root...
Deletei think it ws sq root h/4mw
ReplyDelete2by2 unitary matrix with det exp(imphi) to be converted to matrix with det 1?
ReplyDeletemultiply a row or column by exp(imphi)
chemical potential for Bose Einstein condensation...is it zero?
unit normal vector to given equation of eclipse?
Option A for ellipse question.. what is your answer?
Deleteyeah it was zero 100 percent right for boson gas
Deletethe chemical potential for boson is Ve
DeleteZero is exactly right...
Deleteexactly
Deletei think its 1/2 hw because in case of HO ground state energy is not 0. In case of BEC chemical potential is lowest eigenvalue (energy)
DeleteBut there is also a condition for BEC . chemical potential value is less than ground state energy value ...
Deletea thermodynamic process occurs by 2 waysAtoC and AtoB toC.amount of heat in 2nd...is answer 80J?
ReplyDeletelife time of particles in decreasing order...p,n,pie,delta?
energy extract is 80 j
Delete220 j
Deletei think 220 J
DeleteI think 80j
Deleteinternal energy is path independent but both work done and heat are path dependent quantities . with this in mind first calculate internal energy using formula dQ=dU+dW . then with that internal energy calculate dQ .
DeleteI didnt remember the exact value. I too think 80j
sectionA
ReplyDeletelength of pavement300m
graph for dis covered by snailD choice..the graph with negative slope.
length on earth of river in semicircle...11km
rectagular figure...distance PQ=15/4
area of triangle?
smallest number exp(1/exp)or .33^.33 or .44^.44or pie^(x1/pie)
graph for dis covered by snailC choice..time will not be go back
Deleteanswer (d)
Deleteyes snailC time will not go back
DeleteSure, C is correct
DeleteD is right
DeleteD( having pi's)
Deleteyes answer c is correct time cant be decreased
Delete]
c
Deleteminimum days between fridays 13 to 13....28
ReplyDeleteIn leap year it won't be 28.
Deleteno it is 91 days including leap year
Deleteyes..91 days is the right answer.
DeleteI think it would be 56 days
Deletedefinitely answer is 91 days
DeleteStart from 13th January Friday. You will reach 13th April Friday with February 29 days. So 91 days.
Delete91 as it is a common factor of 7 and 13
Deleteunit normal is option D I+J+K/sq3..because its a special case whn a=b=c u have to take this one
ReplyDeletewas that mention in the question that a=b=c??? i didn't remember .
Deletein unit normal vector it will be option A....you have to take gradient and then satisfy the points given...u will get option A.
Deleteprocedure is correct.
Deletethe ratio between triangle area is 1:2
ReplyDeletehexagonal problm is sq2*a
25%of25% 0f x where x ix6.25%
cucumber is 99kg
you are correct
Deletecucumber 50 kg
Deletecucumber : 50kg is the right answer
Delete99
Delete1:3, sq2*a, 6.25 , 99kg
Delete1:2,sq(2)*a,6.25,99kg
Deletecucumber problem...
Deletefirst water 99% others 1% total weight 100kg... ie 99kg water 1 kg others
after 30 days water 98% and others 2%...
1 kg others remains same till now
so suppose x is the total weight now
ie 2% of x is 1 kg
x * 2/100 = 1
x=100/2 =50kg
right...??
yeah ur right
Delete1:2 is correct...100%
Deletepart B harmonic oscilator problm with (ax) ans is (n+1/2)hw+1/2aw2....u have solve it exactly this is the total correction..obviously those who calculate 1st order correction they must argue that ans =(n+1/2)hw but they asked total correction either if u do it by quantum mechanically u hv to go upto 2nd order...(Zetly quantum mechanics)
ReplyDeletebut expectation value of x operator is zero so this part will not contribute what i think/
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Deleteif you do 2nd order PT you will get non zero term...i think
Deletei think no effect of perturbation
Deletelogic gate choice is A.B whole bar
ReplyDeletecorrect
Deleteyup whole bar A.B
DeleteThis comment has been removed by the author.
Deleteit is A+ B
DeleteNo it is A.B whole bar.
DeleteNo doubt..A.B whole bar..
Deletemodulation problem answer is 6.99 MHz to 7.01 MHz
ReplyDeleteI think it would be 7.0 to 7.01 MHz, as the AMPLITUDE modulation would not decrease the frequency.
Delete6.99
Delete&7.01
direction problem answer is south east
ReplyDeleteNo.. NorthEast
Deleteyes it's right ans.
DeleteNorth east
Deleteyes it is north east
Deletenorth east is right
DeleteI think the opamp answer is 10 Hz and (Pi)
ReplyDeletedefinetely right answer
Deletethe distance along the semi circle is 5.5 km
ReplyDeleteyes.. 5.5km is the correct answer.. Mine is also that... best of luck
Deleteyes that is the right answer
DeleteLeast value is e^(~1/e)
ReplyDeleteyes definitely
Deletefriday 13 th to friday 13 th wont come for the problem .since it is a leap year.
ReplyDelete91 days is the answer..
Deletei think for diode problem the answer is 8V
ReplyDeletei think 2 v
DeleteApply Kvl:10+i+Vd=0 Ans:2V
Deleteratio of triangle area area is 1:3
ReplyDeletenope its 1:2 u have to do likt this
DeletetirADE=triABCTRICBD
now you will gate 3/21
so its 1/2
but i have done by taking formula 1/2*base*height and since height of both triangles are same and base ratio comes out to be 1:3..isnt it correct?
DeleteShruti it's 1:2
DeleteU can do other way by roughly taking Hieght 3 and then assign/divide base in three equal parts as mentioned in Q uestion.
Calculate area of whole rt. traianglle subtract area of rt. triange having two/third of the base, ..U wil get area of the trainle .not right angled (as suggested by swaroop) and then compare with area of rt. trianle with base only two times it comes out to be 1:2.
I would say not write comments on answer if U r not 100% confident
hmm but u knw u missed out one thing
DeletetriADE=TRiABCTRI CBD
nw TRI(ADE)/TRI(CBD)=TRI(ABC)/TRI(CBD)1
now tri ABC=1/2base*height=1/2(3AD)*height
abd triCBD=1/2(2AD)*height
put this together u will gate
TRI(ADE)/TRI(CBD)=3/21
23 December, 2012
nope my account is blockd sorry.thats why i hv to dlt ...
DeleteAnswer is 1:2
DeleteIt can be done the way Sruthi did also. Find the area using i/2*b*h and subtract one from another. You will get the answer.
perturbation problem: ans is 2ab ?
ReplyDelete2ab
Deleteyes, it is 2ab.....do you know the answer of the uncertainity in position problem of part B...is it square root of 5 X h divided by square root of 2...
Deleteyes it was square root 5x/squre root 2
Deletethanks...for your reply....
Deletelength of spring is 10 power 3
ReplyDeletei got same ans
Deleteyup same answer for area 1sqr.m, diameter 1mm lenght of wire is 10 power 3
DeleteYes. 10^3 is the answer
Deletepole and diagonal problem the answer is sq.rt.2a
ReplyDeleteyes definitely
Deletecoin problem the answer is 1947 . Because in the museum old coins will be kept
ReplyDeleteYou really a physics student dear ?? csir made you fool ... the answer will be Year xxx B.C. ... because while printing that coin , none knew that after xxx years , Jesus Christ will born, so it cannot be true... Get it dear ?? All xxx A.D. are correct
Deletemay be its 200BC
DeleteYes. Answer is 200BC.
DeleteBecause after Christ only people started counting year as before and after Christ
ha...ha....200 B.C dude
Deletetriangle problem pythagoras theorem is correct i.e sq.I=sq.II+sq.III
ReplyDeletecorrect
DeleteNo
DeleteIt is I=II+III
becz I,II,III are the area
Yes II+III=I is the right answer
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Deletewhat was the answer of partition function problem? any ideas about cutoff for JRf?
ReplyDeleteU have to score at least 75 for ugc and for csir 85 and above
DeleteJRF 80 MARKS AND FOR LECTURERSHIP 70 MARKKS . THIS DATA IS APPLICABLE FOR GENERAL AND OBC.
Deleteon which basis u r telling the cut off?? is dre any norm about dat??
Delete45 marks last year cutoff for JRF for general.It may +/5 this time also.
Deletefor fermi sphere problm u have to do like that
ReplyDeleteV=4/3(pi)Ef^3
now Ef=h^2/8m(3n)2/3 where n=N/V
for fcc u have to take 4(multiplication factor) put all this in the volume equation divide by a3 u will get the ans .
for LS how much one need to b scored?
ReplyDeleteSEE THE REPLY GIVEN ABOVE FOR SWARUP SANKAR
Deletecontour problem ans was 16i*pi or +16i*pi...does ans changes when given anticlockwise?
ReplyDelete16i*pi
DeleteI think it is 16i*pi
Deleteyeah its 19 pi i
Deleteit is 16*pi*i
Deletei mean 16 pi
Deleteangular momentum problem (ml^2)w/2
ReplyDeletegate problem y= (a.b)compliment
ReplyDeleteyes 100% correct
Deleteyes
ReplyDeletebinary stars root2?
ReplyDelete5 marks qs ka answr..b=curla fr one answer..contour integral..i m confused if its anti clockwise then shud it be a minus with b option as answer.. Ebtropy is minimum? d d first qs of part b..is sqrt rawg/rawnoth..is it?
ReplyDeleteanticlockwise contour is +ve
Deleteentropy is max. at equilibrium for micro canonical
anybody remember that question of peacock and snake moving with same velocity, at what distance peacock will catch snake height 12m n distane of snake from base 36 m...?
ReplyDeleteanswer?
It will be 16 m
Deletehow did u calculat it?
Delete12m
Delete16 m
Delete25% of 25% is X%, so X is......i think its 6.25 %
ReplyDeleteyes it is corrrect
Deleteyes, answer will be 6.25%
DeleteThis comment has been removed by the author.
ReplyDeletethe answer of fermi radius is (12pi square/acube)`1/3
ReplyDeleteyes you are right 12pi/3
Deletethe answer of uncertainty value of momentum (d)
ReplyDeleteanswer of the graph i plotted in mathematica it is cosx/x
ReplyDeletewhy not bessel function?
Deleteit is of bessel fn
Deletebassel function.....
Deletei think it is (e^x)*(cos x)
Deleteyeah ur right
Deleteyes ans of that coin question may be 200BC
ReplyDeletewhat is the answer for the 1.quasi irreversible prcess problem.....2.phase space volume and .......3.the uncertainity in position problem(part b).........plz reply....
ReplyDeletei dnt think dat LS cut off will b above 6265. Bcoz d qstn was bit tougher cmprd to d previous ones. Wat do other thinks?
ReplyDeleteThis comment has been removed by the author.
Delete45 marks for JRF last year
DeleteI think this time for JRF 60 to 65 and LS 50 to 55
Deletenot possible +/5 may be I m sure
Deletewe can't guess about the cutoff
Deletepaper was easy but lengthy so there is a problem of time management
Deletefinding the missing letter the answer is Z
ReplyDelete1prblem form BoseEinstien condensate,Chemical potential for 3D isotropic oscillator
ReplyDeleteAns:3/2 hcros omega
2Volueme of fermi sphere
Ans: (12pi^2/a^3)^1/3
3problem of binary stars, ratio of velocities
Ans: root2
4: Complex function Z^3/(z2)(z3)
Ans: 16 pi i
5. 6 spin half partices
Ans: 14 hcross^2
6. perturbation
Ans: 2ba
7. cosx/x plot
8. Limit n> infinity An+1/An
Ans: 2
9. 91 days in a leap year
10. angular momrntu (ml^2 w)/4
11.
http://en.wikipedia.org/wiki/Bose%E2%80%93Einstein_condensate
Deletelook this site ...you can see that chemical potential is zero for a BEC
In central forces angular momentum is conserved ie,mvr= constant then there is no possibility of root . ans is 2 :for binary stars problem
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Deleteria u r rt
Deleteanyone from life science ??
ReplyDeleteplz provide life science que ??
ReplyDeleteThis comment has been removed by the author.
Delete14x+28y+42z wala que send kro..ans k sath
ReplyDeleteX+2y+3z=7
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ReplyDeletephase space trajectories wont intersect each other. Hence ans is the figure with intersected trajectories.(not remembering exact option ,i think b.
ReplyDeleteoption was of two circles independent of each other
Deletenot independent...intersecting each other is wrong one.
Deletein part a :which of the distance vs time graph is not possible? it is the one with two distances occuring for same time ...
ReplyDeleteyes
Deletehydrogen atom problem:eigenvalue of Lz was h/8?
ReplyDeleteyes....I have got the same answer
Deletepart a
ReplyDeletein odd city even city problem answer is odd number of odd city is not possible
part b
ReplyDeletein a 5 series test what is probability of winning toss by saying only heads and winning 3 and lose 2
it is 5/16
Deleteby variational method with H=(ћ^2/2m )d^2/dx^2 α∂(x) find ground state energy with Ψ=Ae^bx^2
ReplyDeletewhat will be the ans of ising model problem?
ReplyDeleteground state wave function : sech2x
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ReplyDeletei think 10, pi
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Deletepower across load resistance in solar cell?
ReplyDeleteis it 45 watt?
Delete1. variation of vector potential inside and outside of solenoid? 2.time average of E square??
ReplyDelete1. relativity problem, distance travelled by muons?
ReplyDeletewht is the value of n im eigen value problem?
ReplyDeletei think 60
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ReplyDeleteplease discuss more on part c physics csir net
ReplyDeletewhat is answer of cities?
ReplyDeletewhat was ans of lim ninfinity an+1/an?
ReplyDelete