# ► CSIR UGC NET, 2012 June 17, Question Paper, Download, Answer Key, Answers, solutions, Explanations, Comment Here

Home
»
2012
»
Answer Key
»
Download
»
Physics
»
Question Paper
»
UGC CSIR NET
»
UGC CSIR NET-Question
»
CSIR UGC NET, 2012 June 17, Question Paper, Download, Answer Key, Answers, solutions, Explanations, Comment Here

Would you like to subscribe through facebook
www.physicskerala.blogspot.com 2o12

UGC CSIR NET 2012 June 17 Answer Key Comment here with explanation

We can complete the answer key with your help.UGC CSIR NET 2012 June 17 Answer Key Comment here with explanation

Please comment the key only if you are sure about the answer, and also give the explanations regarding your answer.

Question Papers and Answer Key

Comment the answers, solutions, and explanations....

Let your friends know about this page

**Facebook**

Hi, friends there lot of comments, can't moderate on time.. please comment detailed answer and do not comment same comment again and again if your comments are not appearing. Please wait some more time...

**Click Here & Post**this toHi, friends there lot of comments, can't moderate on time.. please comment detailed answer and do not comment same comment again and again if your comments are not appearing. Please wait some more time...

Posted by our guest writer S . If there is any content violations Report the Administrator by clicking "Report Problem".

comment the questions from your memory to construct full question paper.

ReplyDeleteWhich of the following would be the possible blood of child if the parents have O and AB blood groups?

DeleteAns: A and B

A & O.

Deleteit should be A or B. NOT O

DeleteA and B is correct. A and O is possible only when parents have a combination of A & O. Refer Surekha Tomar's guide on Physical sciences.

DeleteCORRECT ANSWER : A , B BLOOD GROUPS

Deleted' < 2d

ReplyDeletesince force*distance is constant. therefore it should be d=2d'

Deleted > 2d'

Delete@Raja you are wrong look question no 100 at100 Questions

DeleteSince the force is force perpendicular to the rod d=2d' is valid( here rod weight is negligible). In the 100th question (you prescribed) rod weight is not negligible.It is comparable to the wight of hanging body. So I d=2d' is correct answer in general question.

Delete@SREEJITH P

Deleteraja is correct, its just balance of moments (torque) about the point of support which easily gives d=2d'.

In the question it is a bar. Then it can be consider the mass. If mass is not considering the answer as per Raja.

DeleteIf we consider the mass of the bar, ?

the mass of rod was not given in the question...........so we cann't consider the mass.

DeleteIn the question it is a bar. for a bar there will be a thickness and width. Also in the figure it shown as a thick line (not a thin line). so we need to consider the mass of the bar. d=2d' is an approximation. we need to select more accurate answer.

Deleteplease reply ..

however in ques mass was not given but it was mentioned that bar is not massless but of uniform mass/length.

Deleted'<2d

Deleteeigen value of matrix [1 2 3;2,4,6;3,6,9] is 0,0,14,

ReplyDeleteMATRIX 1 2 3

Delete2 4 6

3 6 9

CORRECT ANSWER : 0,0,14 are the correct eigen values

weight is same

ReplyDeleteslope 1<m<root3

paper was very very tough

person in center of disc rotating with angular momentum Omega(in up direction)- 2v*Omega to his left

ReplyDeleteS is proportional to T^3. So entropy increases 8 times

Digital electronics question- output in both cases is 1 (1,1)

Dominant multipolarity - E2 and M3

for angular momentum question direction of rotation is not specified,so data is insufficient.

DeleteOmega was given vertically upward so disc was rotating anticlockwise as seen from above the disc.

Deletecan u plz explain the question dominant multipolarity.. i didnt get it

Deletei heard that questions in part c was so tough and most of them are from advanced topics

ReplyDeleteanswer to question lorentz invarients is Esquare2Bsqaure2.

ReplyDeleteop-amp output volate is -1volt

in h parameter ans is voltage gain is 35 and curret gain is -35

no shyam if you will see Irodo's book of electromagnetism ,there it is wriiten that E^2 -c^2b^2 is lorentz invariant.

DeleteMr shyam for your third ans i want to tell you that voltage gain for CE configu

Delete-tion is always negative thats why ans should be -35, and current gain is 35

it is also correct,

DeleteCORRECT ANSWER : E^2 * B^2 is lorentz invariant

DeletePhotoSynthesis is more on the sea level compare with high altitude.

ReplyDeleteThe rate of photosynthesis increases as the humidity increases.

why??plz explain...why not pressure?

Deletebecause photosynthesis depends on atmospheric CO2 and H2O . concentration of both are high at sea level.

DeleteWhy only the humidity and the pressure factor is there ? The intensity may play the factor in case of grwth . .. .

DeleteIs it not intensity of light which is more at see level?

Deletehttp://fhs-bio-wiki.pbworks.com/w/page/12145771/Factors%20effecting%20the%20rate%20of%20photosynthesis

DeleteFriends, go through this for better understanding on photosynthesis

The right answer is pressure. The pressure at sea level is high... due to which the density of air is high. It means the number of CO2 molecules per unit volume of air is more. So the CO2 uptake will be more and hence the rate of photosynthesis.Hope itz the answer of the question.

DeleteWhat about the velocity time graph

ReplyDeletestraight line

Deleteoption a

DeleteCORRECT ANSWER : straight line graph

DeleteCORRECT ANSWER : straight line graph with negative slope is the correct answer to the velocity time graph

Deletepart A maths (1) ratio of population B to A is 1.44 (2) perimeter of triangle is 47.32 (3) area of shaded portion is pi-2 (4) angle of semi circle <APB=<AQB (5) figure suggest that (a+b)2=a2 + b2 +2ab (6) ice melts due to shoes presure of sketer ans is first

ReplyDelete@ anonymous...perimeter is 40

Deletei think the question was the sides of a right angled triangle are in AP . its smallest side is 10cm then calculate its perimeter?

angles are in AP or sides are in AP ????

Deleteopamp ans -1

ReplyDeletedigital electronics ans 111

no of suares is 15

ReplyDelete17

Delete17 is correct. I myself could count 16 and there was no option with 16 and hence can't be less than 16.

DeleteThey are asking for squares , not rectangles, Still can we count 17 ?

DeleteYes 17 are there

DeleteCORRECT ANSWER : 15 squares

DeleteEXPLANATION : number of small squares = 9

number of squares with sides twice that of small squares = 5 (one common is redundent)

number of squares with sides three times that of small squares = 1

therefore total number of squares = 9 + 5 + 1 = 15

gypsum-plaster of paris

ReplyDeleteporcelain- clay

limestone-cement

silica sand- glass

above mentioned matches are absolutely correct

DeleteHow many square was there?

ReplyDelete15

Deletetotal no. of square is 17

DeleteNo Bist that will be wrong answer. The right answer is 15 squares...

Delete[ X2,P2] = ?

ReplyDeleteAns: 2ih[px+xp]

it should be 2ihxp

DeleteThis comment has been removed by the author.

Delete@MUTHU is correct

DeleteCORRECT ANSWER : 2i(h/2pi)[px=xp]

Deleteoutput of digital circuit (1,1)

ReplyDeleteCORRECT

Deleteweight is equal of both jar A and B

ReplyDeleteopamp output should be -0.5 V becoz there is voltage divider at the output with equal resistance so the output will be half.

ReplyDelete-0.33v

Deleteravi kumar g raj nair absolutely right

Deletenair g

Deletefor that question

ans is -1 v

bcz in parallel voltage remain same

we can solve the ckt using th econcept of kirchoff's law.Then we get answer is -1 V

DeleteIn velocity time graph, option (a) was correct because in that fig slope was negative (use this formula v=u-gt)

ReplyDeletePart C: Eigen values of antisymmetric matrix

ReplyDeleteAns: 0, i, -i

wrong. ryt ans is 0,0,0

Deletemr anonymous

Deletecorrect ans is:0,i -i as calculated

bcz jaruri nahi ke antisymm matrix ki e.v.sirf zero ho

they may be imaginary

MATRIX : 0 L M

Delete-L 0 N

-M -N 0

where L, M, N are the components of a unit vector

CORRECT ANSWER : o, i and -i

0, -i, i correct

ReplyDeleteWhat abt d ans of qs..in jet chewing gum helps us?

ReplyDeletepressure balances

DeleteChew gum. Chewing gum stretches muscles in the jaw and throat that can cause the eustachian tubes to open. This allows air into the middle ear and equalizes the pressure. Keep chewing gum as long as the pressure is changing.

maintenance of pressure on both the sides of the person who chewings the chewing gum.

Deletepressure balance is the right answer..

DeleteALL PHYSICS STUDENTS COME HERE.. WE RECONSTRUCT THE PAPER. FIRST LET US RECOLLECT 20 QUESTIONS.

ReplyDelete1. WEIGHT OF TWO JARS QUESTION

2. BLOOD GROUP OF CHILDREN FOR O-AB

3. VELOCITY GRAPH

4. PRESSURE ON EAR DRUMS

5. Y NT SOLAR ECLIPSE ON EACH FULL MOON DAY

6. PHOTOSYNTHESIS N ALTITUDE RELATION

7. AVERAGE SLOPE OF LINE

8. INCENSE STICK SMELL SPREADS FASTER IN H/L ALTITUDE AND H/L TEMP

9. SEISMIC FOCUS OF S-WAVE N P-WAVE

10. SATURATED SOLUTION PREPARATION OF SUGAR ---- GRAPH

11. AA' AT EQUATOR N BB' AT 60* WTS D RELATION

COMMON FRNDS COMPLETE THE REMAINING 9 QUESTIONS THEN VL DISCUSS ANS

12. MASS OF SAND PILE AS FUNCTION OF HEIGHT

Delete13.CARBON DATING

14.NUMBER of SQUARES

ratio of daughter parent nuclei after 2 half lifes

DeleteRatio of daugter parent nuclei after 2 half lifes is 3.

DeleteSuppose any number of nuclei e.g. 1500, (one can take any number instead 1500).

DeleteAfter one half life: No. of parent nuclei left= No. of daughter nuclei formed= 750

and after one more half life No. of parent nuclei left = 750/2 = 375

and No. of daughter nuclei formed = 375 + 750(previous one) = 1125,

So the ratio is 1125/375=3

In the sand pile question there is a word "pile of same geometry" ...

Deletethen , is it mean if the height increase the width also increase? please comment...

Same geometry refers that

Delete1/3*pi*r1^2*h1 : 1/3*pi*r2^2*h2

therefore h1:h2 = r2^2:r1^2. correct?

that is ratio of volume = ratio of the cube of height..

Deleteitz mentioned only about height.so no consideration is given to radius

DeleteFrpm Part A regarding carbon dating

ReplyDeleteBecause the half-life of carbon-14 is 5,700 years, it is only reliable for dating objects up to about 60,000 years old.

So the answer is that the c-14 would have all decayed (dont remember which option -i think D )

yes option D

DeleteCORRECT ANSWER : Almost all of the C-14 atoms would have decayed

Deletealthough CO2 concentration is same in the atmosphere, give reason why rate of photo synthesis is more in the surface as compared to higher altitude?

ReplyDeleteCan you see in top? already, it is there.

Deletethe reaction between hadron, leptons and decay are strong, electromagnetic and weak....

ReplyDeleteIF two different sizes of sand are kept with same height, then volume will be proportional to.....

ReplyDeletea match stick is burnt then where it will smelt quickly...at surface or at higher altitude?

ReplyDeleteTemperature is responsible to spread some quantity, depends on density also. so surface.

DeleteN bosons has to place in two different energy levels...how many ways u can place them?

ReplyDeleteN+1 ways.

Deleteis it sure

Deletethe bosons are identical.

DeleteIf number of bosons are two, then the possible ways are, (1)two bosons in 1st state, (2)two bosons in 2nd state (3)one in 1st another in 2nd. Hence possible ways 3.

If number of bosons are three, (1)three are in 1st state (2) two in 1st state, one in 2nd state (3)one in 1st state, other two in 2nd state (4)three are in 2nd state . Hence possible ways 4.

If number of bosons are four, (1)four in 1st state (2) 3 in 1st state, 1 in 2nd state (3)2 in 1st state, 2 in 2nd state (4) 1 in 1st state 3 in 2nd state (5)all in 2nd state. Hence possible ways 5.

and so on...

Is it correct??!

i would like to know the explanation behind this answer...

Delete@Vijay I did the same way you explained by taking diff values for N.The answer is correct there r N+1 ways.

Deletecheck out this wiki page - http://en.wikipedia.org/wiki/Bose%E2%80%93Einstein_statistics

From that page - "It is easy to see that there are (n+1) ways of distributing n particles in two sublevels..........."

This comment has been removed by the author.

DeleteCORRECT ANSWER : N+1 ways

Delete@Vijay Raghvan has given right explanation

find the perpendicular vector to the surface X+Y+Z=5 (Result may be i+j+k=0)

ReplyDeletetwo white balls and 3 black balls in one container and two black ball and 3 white ball are kept in another container...find the probability to get one white ball from the two containers??

ReplyDelete41/70

DeleteI too got 41/70

Deletea frame is moving with a velocity x m/s with respect to another inertial frame. the separation between the two frames are given y m...find the time interval between them?

ReplyDeletefind the correct operator used in quantum mechanics...-ih (del del phy), -ih/sin (theta) (del del phy) etc...

ReplyDelete-ih/sin(thetha)(del del phy)

DeleteQuestion was which one of them is hermitian operaor and the answer was -ihcross del operator

DeleteCORRECT ANSWER : -(ih/2pi)d/d@

Deleteans of the question of accuracy and precision will be A: Poor accuracy and high precision and B: poor accuracy and poor precision.

ReplyDeleteyes you are correct

DeleteLED with volts 5mV and current 2mp is given. find the no. of photons emitted?

ReplyDeleteA streamline flow of a liquid is shown with a pipe with both ends with same area but the middle area is made lesser...is pressure will b same throughout the pipe or more in the middle?

ReplyDeletePressure is low at middle..

Deletehow?

DeleteBernouli's theorm

Deleteuse the link Click here So answer is pressure is same at A and C

DeleteWhich of these remains invariant under Lorentz transformation?

ReplyDeleteAns. E.B

Ratio between two moment of inertia

Ans. 1.032

SCATTERING CROSS SECTION

Ans. it is increased by four times

FOR an analytic function if u= x+(x^2/2) then the value of v is...

Ans. y+xy

A man on rotating disc fires a bullet with velocity v horizontally. direction of disc's angular velocity w is upwards. acceleration of the bullet is...

Ans. 2mwv in the left direction.

PLEASE COMMENT

is it 2mwv to the right

Deleteratio 1.048

Deleteinvariant is |E|^2-|B|^2 ( Ebar.Bbar was not in the options)

Deletehttp://en.wikipedia.org/wiki/Classification_of_electromagnetic_fields

What is the answer to the beaker and iron problem in csir net math ?

ReplyDeleteWhat will be the pattern of waves of a simple harmonic oscillator when immersed in water...graphs were given..

ReplyDeleteit is just like damping oscillator. The answer is the spiral towards the origin.

DeleteABSOLUTELY CORRECT

Deletethere are two normal mode of vibrations one with frequency w1 and other is 2w1.what is the probability of getting energies less than 4h(cross)w1?

ReplyDeletethe fundamental lines of two molecules are given..what is the ratio of their moment of inertia?

ReplyDelete1.046

Deleteyes thats it!!!! B1/B2=I2/I1

DeleteWeight of jar A and B is same.

ReplyDeleteBecause if we suppose both jars were filled upto brim with water then certainly both would have same weight. Now if we put a block of weight w in jar B, ( as the actual question in paper) then the amount of water that will go out of jar B will have same weight as that of block immersed in jar B (Archimedes Principle) , so effectively there is no net change in the weight of jar B. Hence both jar A and B had same weight.

but if u place an iron block in one jar and water is upto brim in both case then? as per Archimedes pinciple the loss of weight of the material when immersed in water is equal to the displaced water......

DeleteIron block will sink into the water as in that case weight of iron block is more than the weight of maximum water displaced by iron block, hence upward buoyant force could not keep iron block floating and iron block sink down. Then jar B would have been heavy than jar A. However for a floating body (e.g. wood block) ( as the figure was in exam) my above given explanation will work.

Deletethe ans is Vpg-w

Deleteaman is correct,this problem can be explained using the principle of floatation,That is the weight of the displaced liquid is equal to the total weight of the body/

Deleteyes,Aman is correct.This can be explained using priciple of floatation which is the weight of the displaced liquid is equal to the total weight of the body.

Deletewhat is the the answer of part c probability problem??? is it N(N+1)/2

ReplyDeleteNo it is N+1/2

DeleteIt is N(N-1)/2

DeleteThis comment has been removed by the author.

Deletedevender is right. total no.=N(N+1)/2.when we take tha average

Deleteit will come (N+1)/2

can anyone suggest what is the answer of part c probability question??? is it N(N+1)

ReplyDeleteNo it is wrong because it is applicable for BEC probability, but it is asked for maxwellian distribution probability.

Deleteit will be N+1

Deleteit will be n+1

Deletehow could u say that it was asked for MAXWELL DIST.

Deleteit was clearly mentioned that for bosons find etc etc.

so ans is n+1

1)Ratio of inertia for isotope substitution. Answer is 1.08

ReplyDelete2)energy 1eV, and two Temperatuers are given. Then ratio of number of particles proportional to Exp[-30]

3) BEC condensate. Helium gas 21.7mK

Ratio of inertia for isotopic substitution is 1.046. It is given in Benwell chapter-microwave spectroscopy.

DeleteBlood Group Answer A & O

ReplyDeletethe answer for blood group is A and B

Deletewrong....it's A & B

Deletechemical sciences qs:hw nu- attack at the double bond?

ReplyDeletechem sc que: for d5 system microscopic states are: (c) 7*6'2

ReplyDeletewho is Anonymous, why he is replying all the questions.. he has been doing this since last three four year....

Deletedo't mislead your junours..

ReplyDeleteComment all questions completely.. there is a lot of visitor who are not attended the exammake the discussion useful to all ..which one is the best eigen functions for the angular momentas......

Deletethe options are:

H, Lz,

H, L2, Lz

Lx, Ly, Lz

Lx, Ly

The value of magnetic field for a straight wire carrying current I, for a large distanca is varies as

DeleteIf the function as f= 1/(Z-1)(Z-2) then find its laurentz expansion between Z is less than 3/2

DeleteIf Free energy of the system is given then find out the value of system energy

DeleteI have not remember the exact function of free energy value?

If the energy of the system is given 14pihcross square/2ml2then find the best combination of the wavefunctions

DeleteFind the commutation relation of [|r|, |p|]

Delete1.|r||p|

2.r^.p^

3.3

4.1

Best eigen functions of angular momentas are that of L2,LZ and H

DeleteH and Lz

DeleteCORRECT ANSWER : L2 AND LZ

DeleteQUESTION : poission bracket {!r! !p!}

DeleteCORRECT ANSWER : r^ . p^

QUESTION : Expression for free energy F is given. Calculate the Internal energy

DeleteCORRECT ANSWER : 5/2 NKT

QUESTION : The magnetic field at a point at adistance R from aconductor carrying current I is

Deleteproportional to

CORRECT ANSWER : I/R

answer for double potential well

ReplyDeletesaturated solutin graph

ReplyDeleteGraph was similar to that of charging curve of a capacitor through resistor.

DeleteThis comment has been removed by the author.

Deletefree energy given find internal energy ?is it 3/2kt

ReplyDeleteinternal energy is 5/2kt

Delete1.if the black body is enclosed in a box of temperature T and then the temp is raised to 2T what is the increase in entropy..a)2times b)4 c)8 d)16

ReplyDeleteThe entropy in the case of black body radiation is proportional to T^3 . hence the correct option is 8 times.

DeleteCORRECT ANSWER : 8 TIMES

Deleteeigenvalues are 0,0,14

ReplyDeletehey what will be this year cut-off for clearing JRF+LS and only LS....please enlighten me

ReplyDeleteLast time it was 35% for LS and 40% for JRF+LS.This time it may go up a bit like 40% for LS and 45% for JRF+LS

Deletewhat is the answer for eigen values of antisymmetric matrix {0 -n2 n3; n2 0 -n1; -n3 n1 0} where n1, n2 & n3 are unit vectors?

ReplyDelete000

DeleteThree charges -2Q ,Q ,Q are placed each at the three vertex of an equilateral triangle having side lenght = a .

ReplyDeleteFind the dipole moment for this charge configuration independent of the choice of origin.

A) -2Q*a B) -root3*Q*a C) +root3*Q*a D)0

Answer is B) -root3*Q*a

Let us place the origin mid-way between the two positive charges Q such that they lie on the X-axis at equal distance from the origin (a/2)

So the charge -2Q is at a distance (root3)*a/2 from the origin

dipole moment p = summation (q * d) = -2Q * (root3)*a/2 + Q*a + Q*(-a) = -root3*Q*a.

You will get the same answer with any choice of origin you take because when the total charge is zero(monopole moment) then the dipole moment is independent of the origin (Griffith page 151)

answer for the possible blood group will be A & B.

ReplyDeleteHi raj,

ReplyDeleteHow can u consider, in the dipole moment summation, the 3rd term Q*(-a) it should be Q(+a) i guess. I guess the choise of origin should be considered at the middli of the equilateral triangle. Plz confirm.

what is the vale of poission bracket {|r||p|} is

ReplyDeleteCORRECT ANSWER : r^ . p^

Delete@Raj nair; just conforming:

ReplyDeletep= -2Q *(root3)*a/2+Q*a/2+Q*(-a/2)=....

{-------------}this part

how differential scattering cross setion varies when sacttering amplitude doubles in a scatering potential V0

ReplyDeleteLED - no: of photons

ReplyDeleteQ: 3-D particle in a box have energy 14∏^2ħ^2/2mL^2 . its wave function

ReplyDeleteAns: (2/L)^3/2 sin(x/L)sin(2x/L)sin(3x/L)

is it correct

no it is not correct........

DeleteWhy is it not correct?

Deleteisnt it like this nx^2 + ny^2 + nz^2 = n^2 we are given n^2 = 14 so (nx,ny,nz) = (1,2,3).

@ devendra can you explain the reason please?

Delete(2/L)^3/2sin(3x/L)sin(5x/L)sin(6x/L)

ReplyDelete