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I.E.S-{ORJ) 2001\ I ol 14

MECHANICAL ENGINEERING J ~-==::==!

I.

2,

3.

PAPER-I

If N,1 IS the specific speed or a pump handling larger discharges at low heads and N,2 is that or a pump handling low <.hscharges nt h1gh heads, then "luch one of the follo\\ mg IS correct.,

11. N'f1 >N.z b. N01 < N,, c. N,1 = N,.l'

d All the above three are p()Ssible under different situations

Consider the following sl ~temenLS in respect or impulse steam turbines

I Blade passages are of constant cross· sectional area.

2. Partial admission of steam is permissible.

3. Axoal thrust is only due to cbru1ge in now 'elocil) of steam at mlet and outl et or moving blade.

Which of the statements given above are correct?

a. 1. 2and3

b. Only I and 2

c. Onl)' 2 and 3

d. Only 1 and 3

Consider the follo\\mg stntemcms

I. Forward swept blade impeller is used in draft fans.

2, Fonvard swept blade tmpeller is used in room air- conditioners.

3. Radial lipped blade impeller is used in drun fans.

4. Fom•ard swept blade impeller is used in exhaust fans

Wl'uch of the statemc~nts gn·en above is/are correct 'I

a. Only I

b. Only 2 and 3

c. Only4

d 1. 2,3and4

-1.

5.

,,

7

tn an a.xial llow impulse turbine. energy transfer takes. place due to

a. Change in relative. kinetic energy

b. Change iJ> absolute kinetic energy

c. Change in pressure eo erg)•

d Charlge iu energy because or centri fugal force

Constder the followmg

I, Superheater

2. Econon>izer

3. Aor pre-heater

4. Condenser

Whtch of the abcve tmproYe o\ erall steam po\\ cr plant emciency'l

a. Onl~· l. 2and 3 b Only 2 and 3

c, Only I and 4

d. I, 2. 3 and ..t Cons•der the foll owmg.

I h~ector

2. Economizer

3 Bioi\ -off cock

4. Steam stop vah·e

Whtcb of the abore 1s/are not boiler lU0UJ1lU1gs ?

a. Only I

b. Only I and 2

c, I , 2 and J

d. 2 and 4

In a steam nor~le, to mcrease the Yelocity of steam above sontc velocity by e.xpunding s team below critical pressure

a. A vacuum pump is added

b. Rmg diffusers are used

c. DIYergent portion of ~1e noule is necessary

d. Abrupt change in cross-section is needed

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9,

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Wilson line io a~sociated wiUo which ono of the: follow in& 'I a. Totol steam con.•umption with r""pect

to power output:

b. Supen;onic flow o steom (hrough ~ noz7Je

~. Nozzle Oow l'' ith tiiction 11 Sop<m<atuo':lred Jlnw nf sremn thmug)o ,

noul~

Which one of the ti>llowing expre<>es the ma.d mtun blad~ efticien~v of a Par< on ·~ turbine ?

'2co•' a •• 1• cosl! a

cosla b.

1- 2c<>S' a cos a

c.

d. cos (i(

2

where a is th.o ,iet angle at the entrance.

When is the greate:;t economy ohta ined io :o '"generative feed heating ~ycle ? a. Steam. IS extracted from only one

suitable poim of a steam turbine

b Steam is oxtroeted only fTtJm the las! Stage Of II <team turbine

c. Sl~•11 is e_«tractcd OnlY from the first Wlllf!t of A steam turbine

d. St~am ;. extracted from $Wera t places in dilf«cnt sl og<>s of stc:;~m turbines

lu a rcac!ion turbine tlte enthalpy dl'OJ> in a st>g11 U. 60 units. 'Ibe enthalpy drop iu tho moving bbdes is 32 vnil3 .

Wloat is the degree of rca.:tion ?

"· 0.533 b. 0.284

c. 0.461)

,1, 1.875

Which of the following C.'lll be the call."elcau.~ or rm air-cooled eompres~or getting uvcrb~tcd dUl·ing C/pttauon 1 1. Insufficient lubricatinj! oU.

2. Broken valve strip.

3. Clugsed iutnkc lilt cr.

13.

I"'

15.

16.

17.

~ <>I I~

Seleet the con-eel answer using the code given beiC>W : a, Only 3

b. Only 1 and 2

c. Only 2 and 3

d. l. 2 and 3

In a cenirift•gal compressor. how can the l>t'\;S.sun.: r:ttio be increased ? a. Only b) incre:osing Ute tip speed

h. Only b) decreasing tloe mte1 tcmpcrulllrc

c.. B)' b<Jtl• • · and h. d. Only hy increasing the inlet

temper:~ture

The power required to drive n hubo­compressor fur ;a giveu pressua" ratio decretHh~S w ht:u

ll, A.ir is heAled at <:olry

b. Air ls cooled a1 entry

c. Air L• cooled al exit

d. Air is healed a l <lXil

Il l an •xioi now COI'CI)trt:S80r. WU<::tl lhct degree of reaction is so• ... il implie8 lhnt

"· Work dono in eompre~>ion will be the leo.• I

b. 50% J tnges of the compressor will be ine.llOCHve

c.. Pressure nftar compression will be optimum

tl. The comt1ressor will h:•vo M)'lnme1ric;tl

hl~<les ·

In Cllsc of hqmcl$. what ,;; the hinory dift'usiOii "')ctl1cit nt proportional to'/

a. Pressure only

b. I'c.mperature onJ~·

c. Volwno oJily d. All the ah•lVe A copper block and an oir mass hlock having similar dimensions ar¢ subject,..! lb symmetric~( heallransfC:r from one fJce of eodo hlock. The other face of the block will he reaching to Ute same tempernture at a rate

a. F""tet in air block

b. F""rar in copper block

c. Equnl ln uir •• woU 3ii copper hlook

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19.

20.

21.

22

23.

d. Cannot be predicted with tho s1ven infonnntion

l'he equation of etl'ec.tivenes.•

E 1 - c~'IV fat a heat t.::<ch..,ng~.-r is valid in ihec.;Heof

a. Boiler and condc"scr for p•nllol flow

b. Boil<lf •nd condenser for count~rflow

c. Boiler :md condtmser lilv hmh par•llcl Oow and onunterllo"

d. Gas tut·bioe for both pa•·•Uel !low and countcrllow

Tb"mtal diffusivity o[ a substan~ is

u. lnve,.,dy proportional to thennal cQntt\lctivity

b. Dir""lll' proportion•! 1<1 lherm:tl oonductivity

.:.. Olte\ltl)' pmporllooal to the S<jUat" of l.hcnnal conductivity

d. Jnver•ely proportion> I lt1 the squ•"' of thermal condU<:tivity

Air cun be be-l ll<!nled by •W.m in • bc.tt exchanger of

". Plate type

b. Double pip<: IYP" witl1 £ius on sloam side

o), Double pipe typo with fiM on sltsido

d. Shtlland tube lyp<:

A IT1ttal plate ha~ a surt~ce are.• ol' '2m'. tltjclme.s!l lO mm and a thotmnl conductivity of 201) W mk. \Vbol is tho lho:rmal rcsi$t.nnce ofthe plate ?

.~ 4 1 o~ .K/\V

b. 2,5

c. I.S

d. 2S

10 ' KtW

10 'K'W

10·5 KI\V

Wb.i~b 0110 of Lhe foUow iug l;):<pt·os>es 01e therm;al diffusivity of a subst.an.::c in Lcrms of thermal conctu'cth·ity (lo. mass density (p) and specific heal (c) 1

a. k2pc

b. 1'pkc

c. k/pc

d. pcik'

Wbat is lhc rntio <tflh"l'lllal conduotivity 10 ei<>Ctrienl conduclivily equal to 'I

n. Pl-:~ndll number

24.

25.

26.

~ ut IJ b. Sclunldt number

c. Lorenz number

d. L""'•C. number Motch List - I with l.ilit -II and sdect 01e correct nns11 er using tbe code given below tbe List~ '

L ist • 1

A Radiation he.•L U-alli!fer B. ConduGlion heal transfer

C. Forced oon<·ection

D. Transient heat llo11 List · U

1. Biots number

7.. Y icw lilctor

~- Fourier's l>w

4. Sl.1nlon number

•• A

4 0

3

c 2

D

b. 2 4 J c. 4 2 -~

d. 2 3 4 l

l\f:olch List - 1 witb List • n and select the con-eel ons"'er using the code given below the l.i~U. :

List • I (Ph~nomcnon)

A. Transient conduction B. Ful'ced con,·ection

C. Mass truMfet•

D. Natural convectioo

List - U (Assodairo l)imensioniiiS~

Pjlram~ter)

I. Reynolds numher

'2. Grashoff numher

3. Bioi numher

4. !Vucb numbeo·

5. Sbt:rwood nut11ber

~.

"· d.

3

5

3 5

fl

2 1

l

1

c 5

~·

s 4

f)

2

2

Whicb on« of tJoo following is Uoe e<ttt-ect siMeuHml '1

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30.

A nuclear fiSsion is i~itiatcd when thu criticul energy us C<llllpllrcd to neutmn hindin!). <nergy ntoms is a. less

b. sam~

c. more

d. cxnctl) tWu Limes What is the Oash point or a li4uid fuel ?

a. fltc tcmpcrumrc ut which the fuel ignites sponttmcously with a bang

b fl1t te.mpernture nt whrch the fuel emiL~ vapours at ~ rate '"hich prodt•~e~ un inllammahlc mi:<"turc with air

c. The lijntperuturc at which the fuijl ignites with a clearly VISible Oush

d. The temperntlir•· at which the fi1cl ignites without a spad'

What IS t.he function 0 I' hcuvy water 111 u nuclear reactor?

a. It serv~s us u .:onlant b It serves as a moderator

<:, II serves as a coolant ns well as a modeml\>r

d It Krvcs us a neutron absorber Consider the loii<)Wing stmcmcnrs :

The ~asc~ measured dirccLJ y h) Orsut liPIIRriltus front n Oue gas stunptc urc co1. 0)1u1d N1.

2. !3omb calorimeter meusur~s hlgher caluritic value , r fud m constant pr~ssure.

3. For burning I kg of fuel (carbon) 10 curl>on monox1de. the stoichiometric quantity of air required is 8/3 kg.

Which of the st1lll'111tnts given nbuw is/arc corr~ct 'I a Ullly I

b Only 2 c. Only 3 d LlandJ

In ~ vapour Cf>lnpres~IOfl refngcrntion cycle for makmg tcc. the condensing tcmpcratlli'C" tor h1gher COP a. Should be nc~r the critical tcmperlllltrc

of the rcfrigcmnt

b Sht>uld be utxwc the cnticul temp11ruiure of the refrigentnt

31.

32.

33.

34.

t uf ll <:. Should be much below the critical

temp<.,nuurc ofth~ l'l!frigcram

d. Could be of any vnlue liS it docs not ofli:ct the COP

. s

fhe t1gure !liven above depiCts saturation dome fur w.mer on the tcmpermure-entropy plane. Whut l~ Lh~ temperature difference .1 T shown on n typical ISobar line known as• a. Dcgrc~ <If wet bulb dcprcS~ion

b. Degree o I' saturauon ~. Degree of sub~ooling

d_ Dcgrc.c () f rcltcat

Whnl does application ur centrifugal urr compressors lead to? a. L11rgc frontul urc(l of uircruft

b. Higher now rdle 1hrough the engine c. Higher aircrnfi spec<l

d. Lower frontal urea of the llllcraft

Con>idcr the following st:ttement£ indi0111ing a comparison b~twcen r<lC~et and Jet propulsion ~yslcnts : L !3oth rocket :md jet engines corry the

fuel nnd os.idlllll

2. Rockel' do 11\lt employ compressor or propel! or.

J. R<>ckets can orerntc 111 vncuum also. 4. Ruck~ts can use solid ruels and

oxidantS.

Wltich of the statements given above nrc correc.t'l :t I, 1.. H nd 4

h. Only I nnd 2 c. Only 2. 3 and~

d Only 1. J ao<l 4 Whar· 1s the pnrpose or employ ing supercharging for nn engine ~

a. To provide forced CO<IIiltg ttir b. To mise exhaust prc.ssurc

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36.

37.

311.

~. To inject execs~ ruel for coping wiUt high.:r lo~d

d To supply a.n ontake of air at a dens ity greater than the dens ity of the !Surrounding atmm~pherc

Coru ider the following statements ·

I . Superehnrging ln~reas.:s the p ower I. •

outpU! o ao engmc.

2. Supercht~rging increases the hr:ak~ tltt:tm>l cfficit:ney considera:bly.

3. Supereharsirlll help• scavcngin!l oJ cylinder$.

Which of the s tatement> given abov" are corr..:ct ']

:c Only l and 2

b. Only 2 and -~

c. ( lnly I >net 3

d. L hnd 3

'Where does rnixing of litel •ud alr luke plnce in case of diesel engine 'I

"· wjccliocJ pump b. lnjoetor

ll. Engine eylfnder

d. lnleLJnani fold.

C'ons i4er the tb llowiog Rtntements :

1. ln the Sl tau!.ines detonation occurs ne:J1' U1e end of combustion whereas in Cl engin~ knocking 0\..'CUI'S near the b~giuning of oorubusti~n.

2. In Sl engines no problems are <;ncountcred on account of pre-igniliotL

3. 1.ow inlet prtmurc and tcrupcr<~lUt'e ruduc" kneeling tcndtn ey in Sl engines bnt increa•e the knocking ten~en.:y in ("I m gines.

Whicb of the st:ctemeni• gJVen ahow >re C\)ITClCI 1

a, I, 2 and J b. Only I and 2

c. Only 2 and 3

d. Only I 011d 3

The tendcnc) Ill' petrol to di:IOMte in terms of octnnc number is d<.etcrmin()d by comparison of fuel with which uf the following1

ll~ l.so-oct:me

39.

-10.

42.

S ut I~ b. !'vru.:tuno of nonnol heptane :md ls<>-

oetane

c. Alpha methyl naphthalene

d. Mixture of molhnnc and cllmnc

For tltc srune indicated work per eyclc. mean speed and permissible lluct\J~tion of speed. what is the size or ny,,hcel required for o mulli-cylin(ler cn11inc in comparison to a single-cylinder cngind']

a. Bigget•

I>. Smnller

c. Same

<1. Depends on th~nnnl dliciencJ nf the engine

Con~idcr the following swtcments:

I. For n Oiosol cycle. ll1u thermal etticieooy decrenses"" the cut ut'fratin incrca.qe~.

2. In a petrol engine tile high voltage for spark is in U1e o1·der of I 000 V

3. The mote-ti•l l'or centre electrode in spark plug is COJ'h OIL

Whic)l of tl>t statetnen~• £!iven ah<J\ t is lare cnrrtc.t ? a. Only I

b. Only I and 2

c. Only 2 and 3

d. l, 2 and 3

Con•lder lite folio\\ ing •t•l~-naettl> :

\ ·ulumetJic e fficiency of a recip!1loat.ing air compn.:ssor iucn::tsQs with L increa•c in clenronce rJt.io 2 decre.1sc in de~iwry pre.snre

3. multiytaging

Which oft he st.:ttemcnts given above isi:U'\! correal V

a. Only I :md2

b. Only 2 and 3

c. Only 3

d. I. 2 and 3 Whnt is the prel'etTcd int<>reooler pl'cSsore lilr a two Stage air comprcgsur working helwet:n the suction pre-~.sun: p~ and U1e delin:r~' prtssu.re pa? a, (p, 1 p.1)12

b. (p4- p,)l2

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46.

c. (p, P•)' ~

" · (p. • rJl'', Consider I he lollowing stntemems:

In order lo prcvcul detonation in n spark­tgpition engine, U1c churge away lton1 th~ spark plug should have

I, '""' temp<'rtllurc l. low dcosit)•

3. long ignicion delay Which of the swtemems given above is/are correct ? s. Only I

b. Only 1 ~ Only 3

d. I. 2 and 3

--=EG=L:.........-/

The energy grude line (f.GL) tor steady now in a unifonn diameter pipe is shown above. Whicb of the l'ullll\\ lng items is contttioed in the b;lx ?

a, A pump

b. A tlU'bin<

c. A pnrtinlly closed valve rl, An nhn1pl expansion

A compou11d pipeline con~ists of lwn pidces of idemical pip~s. The ettuiv:~Jen• length of same diam~tcr and same frictitm factor. for the compound pipeline is L. 1 whe,n pipt.'"s ore connccLcd in s~.ric..•$_ and is L, when connected in parnllcl. Whal is !he rutio of equivnlenl lengths Loll :? a. 32 : I

h. 8 : I

c. 2 : J

d. ../1 : J

For irrota1ioual and incompn:ssiblc now. U1e velotity polemiul und su-e:m1 !unction are given by <II and II'· respectively.

Which on< of the following sets is co~cl')

a 'J1•r = 0. V2•t• : 0

<17.

49.

50.

b. V'1p '" 0. V'w = 0 c. V2<P = o. v2~1 "' u

' 0 ' 0 d. V'IP ~ • V·•v ~

h of II

In o two-dimcnsinnal incomprt\~lblc steady now, the velocity component u = Ae' i~ ()btaineu. What is the order component" of velocity 1

.'

u. v :: t\e"-~

b. v=A~'

c. v = -Ae'y + ltxt d. v = - Acl >;- lb·)

For n c;;lcudy twt1 .. dbnc:msic•nul now~ tbc sCttlnr componencs ofthe velocity lield are V, = - 2x: V, = 2y, V. = 0. Whut ure the c0mron~niS of acceleration ? o. a,. = 0, n, = 0

b. u, = 4x. a, = 0

c. u, = 0. u, "' 4y

d. a, = 4x, u, = 4y

Consider U1e follo>Ving statements regarding a pa!h lin~ iu lluid Jlow:

I. A puth line is a lim: truceu by a single particle over n time inlcn•aL

1. A path line shows the position~ of~'" ~ame pat1idc:. at successive time instmL~.

3. A pmb line sho\\s the iusmnumcous positions of a number of particles. passlng ~cruugh a common point at some previous time insiJJms.

Which of the stolcmcnls given nhovc nrc correct?

a. On ly I aJ>d 3

b. Only I and 2

c. On I)• 2 am! 3 d. I. 2 and 3 A l>eakcr of water is falling l'r\.>ely u•1dcr the influence of gruvlty. Point Fl is on the surlilce and poiLll {' l-; \'cnically below B near ~te bottom of~~~ beaker. If P is ~1e prcssurc at pilint B and P tl1c prcssul'l! at point C.then "hich nne nflhc fi• ll•)wing is: COrT"CCl 'l

~ Pn = P1

b. Po < Pr

c. "" > 1\

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d. Insufficient int0nn.1tion to cl<ltennino any of t he: above

51. A homogeneous solid of any arbitrary shape flools upngbt in a homogeneous liquid with inunen;cd volume \ and is in stuble O<Juilib•·ium. If Otc solid is MerllJmed and made to J·loot upstde down in a difl'crent h1lmOgcneous liquid with <*actly MOiftt vuhuno V >hovo Inc liquid surface__, lbcn lhe cctuiJihrium a. Would be stable

b. Wou ld be neutral c. Wou ld bc: unstable

d 1\tay or •n•y nor be •tnble 52 A 25 em long prlsmotic homogcneQus

solid float~ in water wid1 its ~xis verticnl and JO em projecting above water s urface. 1f th" snmu soJjd floats in son1c oil wiUl OXJS vcrticnl Jnd 5 em projecting above the liquid surface, what ;, lhe spedflc grnvily Qf thc oU ?

• • (),6()

b. 0.70

<;.. 0.75

d. 0.80

53. A semi-cin:ular plane area of diam<leJ' 1 m. 1~ rubjcctcd to a uniform gas pressure of 420 kN/m!. \Vhal JS the moment of U~rust tapproximately) on the area "bout il~ s~·:Ught ~dge 1

54.

55.

11. 55 kNm

b. 41 kNm

c. 55 kNm

d. 82kNm

A hori:z.onbll oil tnnk ;, in lhe ~hap~ of • cylinder w~h hemispherical end•. If il is exactly half full. what i• the ral!o of mngnitudc Cof lhc vertical C<Jmpon.t'Tll ilf rcsulto.nl hydrostati" tllfUSt on on" ht'flliBJlhoricnl end t.o, U1a1 of tl1c hmizonL1I component'/

" · '2Jn b. n/2

~. 4/(371)

d 3nt4

Tite A;tnnd!lrtl nluto"phoric prosl$UfC i ~t 762 r»m of llg. At a specific loc,11ion, lhe IJ•J<Qmctcr read, 7tHI mli1 of Hg. A• thi~

7 ol 14 piAco;, what does an 3bsolut" pJ'I:ssuro of 380 mm ufHg correspond to 'I -a, 320 mm of Hg vne-aum b. 382 of Hg vacuum

c. 62 rom of llg vnouum

d. 62 mm uf H~j !!•ugc 56. A manometer is n1ade of a tube of uni fom1

boJ'<l uf 0.5 cmz CJ'Oss-sectionnl areas. with on< limb v<-or·ticol nnd UJo other limb in.clined >I 30° lo the hori:z.onto l, Bolli nf ils limbs are open to ;•lmosphere and, initially. it is partl.v filled with 4

manometer liquid of •r ccilic w·•vity 1.25. If lhen nn >ddilional ,.,,hlme or 7.S em" or ""'er i• pc1ured in lite inclined tuhc. whal l1 Ott •·ise of tl1o monillc.u6 in lbc vcrtiClll luhe? a. 4cni

b. 75cm

c. 12 t111

d. lh'm 57. A vertical clean glass tuba of unifom1 bore

is- u~ed, a~ a pie7..ometer to measnre the pressure o( liquid at> poinl The liquid bas • specific weight of 15 kN/m3 aud • surf~cc len.>1on of 0.06 N/m in coniMI 11 ilh a it. It' lor lhc: licWid. the JlngJe of w11L'cl ~<oth g1<1$s i• £cro 3nil th~ capillary cisc in Uu: tube is not to 1::-;cccd 2 mnL whnl is the required minimum diome!Of' of the tube: 'I

S8.

59.

a, 6 11111'1

b. gmm

c. 10 m1rt

d. 12mm

When the JlresstJJ-e on 11 given mass of liquid is incr~~~>t«< from 3.0 I\1Po to 3.5 MPa. the density of the li~id incre.ucs fTom 500 kg'm' to 50 I kg/m . What is I he avernge va lue of bulk modulus of (h., liqujd over tJu.t given pressure runge '1

a. 700 lvfi' n b. 6(K) MP~

c. 500 tv!Pn

d. 250MPo.

A.-slll'lion (A) : Nozzle control guvcrnin.g cnnnol ba o~ed tn reaction ste.am turbines. Rc3~0n (R) : fn l'u;&c.liou ~team h~rbim::s.

rul l iorlmi•s icm nt'srenm must lake place.

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61.

62.

63.

''· Both A and Rare individU4lly !nrc 1md R is theC()rrect e:q>l•n~tion of A.

h. Both .\ ond Rare individually tme but R is not the correct explonalion of A.

c A is true but R i< fal~e d. /\ is fR l§c but R is true

Assertion (A) c Fire tubo huilo~ de.• 11111

opomre at high J)fC!iSUrel< whjle water inhc hoi\ers ''l,eratc: at high pressures,

Rea.on !l'l.J Oue to high temperatuN of llu.e ga<cs. fire tubet; ma~ fail due to creep. a. Both A and R "re individually lme and

R is ~re C<Jrr'ect explanatjon of A.

1>. Both , \ and R are lndividuallv true but R is not the ~orrect e.~planati~n of A.

~. ,-\ is tme bul R ~~ f•l'e tl A is fn loe hut R is true

A .. er1Jon (Al : 'r be internal en.,gy depends on U1e internal stare o.r a body. •s dt>temtined by its tempmwre. pressu~ ~and compo.!t ilion. Re:oson (R) : lntduJal ~ncrgy of a suhstanc« docs not include nuy energy ~rat it may posse-ss a~ 3 result of its mo.1croscopic position or movement. n. Bolh A and Rare individ11.1lly true nnd

R is tl1c correct e>.vl•n~tion of A. h. Both .-\ 3nil R :<re j0dividunll)' true hut

R ~>; not tl•c correct -.~rt•n•tiot> of A.

c. A is true bul R ls false

d. A is false but R is true A .. ertion (AI ; ·noc change in nvnil:rl;rility nf a •ystem is equ•l ro the ch:ange in !he Gibbs tlmction or th~ system at constant temperature and pressor~.

RcallQn (R) . Tbc Gihhs 1\Jnotion i• •l•¢ful when cvaluntjng. Utu avuibbility of syes-lcul)j in wbich chemical reactions occur. 11. BoUr .\and Rare individt1.11ly truo 11nd

R is the correct e:q>lonution of A. b. Both A and Rare individlllllly ln..: hut

R is not the correct explnnation of A. c, A is lmd but R is false

d. A l. fabe but R i• true

As$cr1iOn (A) . All t:()nslanl ctllfll(l)' processes are adiabatic, but oil odiabutic processes are- not isentropic.

64.

6S.

66.

61,

8 of I~ Reason (R) : 1\n ndial>atic process whi.>h resists the exchonge of energy to the surroundings Tnll)' hAVe irrevt:rsibillty dUe

to friction ond bct~t c!Onduciion. lL Both A and R Jrc individunUy lmd and

R i~ the C(11"l'l;;ol explanation of t\ . b. Bolh A und Ran; Iudividuall) !I'll~ but

R is not tho correct crplnnnlion of A.

c. A i> true but R m Grise

d. A is folst but R ;. true .-\sscnion (AI : At "CI) higJT densities, <!llntprt:llsihilhy ut' a teal gas is le.s than om:,

Rc:oson (RJ : As ~.c k'tllperntw·c i>; consjdemhly reduced, tho molecules >re brought "loser togetlrer and t11ermqnuclear attractive forces b~come greak.'1' at pNSSurcs aroLWd ~ 1\U>a.

• · Bo~• A and Rare individuaUy ll'llt: and RU. the cor:n:ut c:<plruwtion of A.

b. BoUt i\ •od R •re 1ndividWllly tru~ but R is not the coLY«·' ~~plnnntion of :\.

c. A i> true but R is false

d. A is false hul R is true

Which one of the following is used to bring down the speed of .on impulse s1<'111ll turbine to pnactical limil-; •1

•· A cc'TltTifitg•l gownuJr

b. Co•n1>ounding nf U1c turbine c A large Oywheel

d. .\ senr box

Con.~tider rhc IOllowing fiw :1 stc:.:.11~1 tlll1hine pnwer pllmt: I. Reduction in blade erosion. 2. lncrcasiJ ln turbine speed.

3. lncr.:asc iu specific output. 4. h•L~e in cycle dlicocney. Which or tl1e ahove occur/occur.o due to rehcnting vf ~1Co1m'l

a. Only I

b, I and 2

c. I. 3 und 4 d. 2 -uud 3

Cunsid~r 0•• lollowing features fur· a g•rs lw·bin~> plnnl :

1. 1111-.'tCOO!i.ng 2. Rc:g~11eratiun

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6'9.

70.

3. Roheot Which of the abow fcJtutts in n ~implc go$ turbine cycle increase the work ratio'/

"· 1, 2 and 3 b. Only l •nd 2 c. Only 2 an<l .~

d. Only t and 3

Which of ll1e following parameters decre.'ISe across 3 no1mal shock wave'' I. Mach number

2. Stat ic tlfessl\fe 3. St.:l.g.nation prc..-s.surc

4. Static tempecalUI'C Select the Currc:ct an~Wcr 11.'>-ing thd code~ givcu below :

a.. Only I >nd :>

b Unly 2 and 4 c. I. 2 and~

d. 2, 3 nn\1 ~

Wllt11 •ro shock wovos formed iu air compn:ssol"'1 a. Moth nurubur < 0.9

b. J\iacb number . 0.9

c. t .. fach numher = 2

d. Msch numl>er changes suddenly ii·om one ·va lue tu :mother

Which nf the followinl! s tatemen ts are con-<:<:1 for mult.i.stagiug in a rc:ciproculing nir comprussol' ')

J. lt decreases the volumetric:. c:flkicrtC")'. 2. The 1\urk done can be J't;<l\Jccd. 3. A ~n1a ll hi&h·pressure cylinder is

ot quircd. 4·. ·n,esize of flywheel is reduc<ld.

:;elect the correct answer II.Sing the codes given belou :

~. L land 3

1>. 2. ;\ ond .I c. 1, 3 and~

d. I .. Lind .I

Whal is the rntio or the iSL'f\lrOI)IC \I'OI'k to Euler's work lulown as ? oo~ Pressuo~ co.::ffid1011l b :;tip ractoo' c. \V c>rk foetor

72.

73.

74.

75.

., "' 14 d. Degree of re3etion Consider ll1c follow ing sblemenls ~

For ;a lArgo Il\li.Jtiou gll!l turbin"'r nn axial Oow eompressor is usu:J Uy preferred O\'lll'"

e<mtrifugal compressor because I. the maltimum efticicncy i8 higher;

2. Uu: front~ I tareo .is luwc1.

3. the pressure nse per stage ;, more.

4. the cost is lower. Which of the s~~tements ~lwn above ore correct. 7

a. I and 4

b. Only 1 and 2

c. L 2and 3

d. 2, 3 and .j

\Vhotare l.be general e<,>mfort cnnditi~J~~ ln a.u •ir-oonditioni.ng sys[1.1u ?

u. 20"C DDT. 80'lo RH b. 24"C DBT. 60°o RH c.. 25°C DBT, 4()<!. RH

d. 25"C DBT. IOO"o RFI Titc bent lood .from the occupants in air­conditioning load ca lculation L• a source of:

a, Sensible heat only

b. Latent heat on ly o. Both sco,.iblc o11d lntcut bc~t

d. Noue ofdte above

\Vhnt is ohc st:~~Siblc hear tltctor during the healing nnd lrurnidllication process e<tual to ''

~-Ill • liz H, - II,

b. H1 - R, !!, - H ,

c. H,+ H, H, - H,

d. H, - H,

fi , - H,

\Vherc~ H_a Tob l beat o f atr cnt~Jring the heating coil H, Toul heat of nir leo,~ng tbe healing co~

HJ : Toltll hent of air nt the end of th e bumidificatlon

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76, \\~tut is Sol-air cemp(wJturc ?

77

7N.

19

a. It fs cqunl '" the stun <lf omlloor nir lcmpernture, ond absorbed fotoJ radiation dn~ded by outer surtucc convective hem transfer coefticient

b Tt i~ equal tu the uilsorbcd total ra(limion •1ividcd b~ c~mvectfvc he~u transfer coctlicicnl at outer surfucc

c, It is equoJ to the total incident radiation divided by convective beat transfer co~nicieru ut oUier surt:-.ce

d It i;; equal 10 the sum of indoor atr tcmpemmre and nhsorbcd toW r!ldintion divided by conwctiw heat transl\:r coeflkienl at outer surface

Which t)'pl! nf vul\'eS is generally used iu reoiprocruing t•cfngcrnnt cumprcs.•or• ·)

a Mushroom valve b Puppcr valve c. Plull: valvc

d. TitrOIIIe valve

Con~ider the f\llhJwfng stntcmcnts pertaining to duct design

I. AspectralJO of dueL' should be big.h.

2 lnlhe equul frictitllt mothtJd uf d~'ign, usc of damJlNS cannm be ~liminmcd by any m~ans.

3. The sta1ic r.:guin method is not suilablo for long ducts.

.J The vclocit) reducl~t'n m~thod is employed only in simple systems.

Which of lhe srntcmcnts given ah(li'C ar~ correct 7 a I and2

b. 3 :md 4

c. I and 3

d. land4

Mmch Lisl - I 'dth T ist • II and select the corr~c1 answer using tJJc cOd'c give11 below lhe Lists List- I (Apparatus)

''" S<pnnrtiog calorimeter B. Throttling calorimt~tcr C. Sling psychrome1er 0 , Ga• thermometer

I isl - 11 ( nlcrm ud )'l11111lic pr!)CO:SS) I Adiabatic process

80.

8L

M2.

83.

f!J ot'JI 2 Isobaric proc<:SS

3. lr..1.:horic process .j lsenthalpic process

A 0 c n a. I J 2 4 b. 2 4 3

" 4 2 3

d. l 3 4

A lhemJoelcc&ric engfne "hich consisl~ of t\\'0 dissimilar dcctrk conduch1rs connected at two junctions mointaincd nt difli: rcnl lcmperalurcs. convcrls

a. Electric energy into heat energy

b. H<at energy inll' tle~tric energy c. Mcchanioal work into dcctrlc cntlfg) d. Electric energy into mechanical work

4

p l (kPa)

2

A

I 8

c I I

0 2 4 6 8 10 12 14 VOlume (ml)

\Vhoch nne or the following is the correcl scqueoocc Ql' Ute th.rce pmccssc.~ A. B omd C on the incr~a.~in~ order of th~ amount of work doo"' by n gas following idoal-gas expansions by these processes o

H. A·ll-C b 13-A-C

c. ,\.C-B d C-A·Il A Cnmot ref'ri!temtot ha; o COl' ot 6. Wbnl is the rati~ uf th~ lower 10 lhe hi~l<!r absolute lempcra!Ures 1 D. t/(, b. 7/8 c 617

d. 1n A heat sour1.-e H 1 cun SliPilly 6000 kJ/ mln at 3oo•c and ru1ollter heat source ll2 cun ~11pply 60000 kJ/min at 1 oo•c Which on~ or Ute liJIIowing statement~ IS correct iflhc surround in~ me at 2 7°C ?

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om84.

87.

a, Bolh I he hea1 sources have We- s.nme crrtcicnC)

b TI.e fir.ll heat sou.w has lo11er rfficicnC)

c. The second heal source has lower efficiency

d TI1e first he,, l source prodtJoes hisJ.er power

According lo the Clapeyron CqMtion, which one of' the following gives the. slope of the saturated liquid pressure lempcmlllr~ CIIIVC dp/dT/ (suffix I' and g denote sawoalcd liquid and S>Jiuralcd vnpour l'eSpeclivcl)')

a, (u, - 111 )l(v, - 1·1)

b. (11,-111)t(v, - v1 )

c. (u. - 11 1 )t[T(v, - v1 ) ]

d. (h, -tr1 )1[1' (v,-v.r }] Wlud1 u11e of the foUowiug is tho chnrnclenstic cquatioll Qf n ocal gns'l a, (p-alv' ) (v- b) = RT

b (p-a!vl)(v +b) = RT

c. 17" = RT

d. pv= nRT

0 10

WbJcll one of the followmg ts com>cl lor the process 1-2 showu nbove '' a. The partial pressure of wntcr vapour fn

nir remai ns conslnnt

b. Specific 1iu111idity of air "''""ius 001lSl3.Ul

c. Enthalp)' of aor ren~•ins constanl d. Dl)' bulb lt!lupomou•e of ait •~mains

co11Siant Cons1der Uoc foUowing stalcrneuts ]JCrtaming to the Clapey ron equallon .

$8.

89

\Ill.

lJ of H I. ll 1s useful to eshmnte properties like

cuthalpy from other measurable properties.

2 At a change of pllliSc. ll t!Ul be used to find the latent heat at a given press11te.

3. ll is dcnvcd fi·o"' the •fillatiotlship

(i'Jp) ( ~) 8v

1; flf •

Wlucb of lhc statcu1euts given above arc coo:rect 'I

a 1. 2and 3

b Ouly I and 2

c. Only I nnd ' d On]v 2 and~

A 12 em di.aoueter suaiglu pipe is laid no a umfonu downgrade 11lld Oow rote IS

tnmntmncd snch lh~l vclocllv head in the pipe is 11.5 m. lf the pressuro' ln the ptpe ts observed to be uuifonn along u.e length "hen the do1~n slope of the p1pe is I in IU. wl.,t is lhe f riclionl;, ctor lor the pipe '1

• . 0.(1 12

b. CUll~

c. (),(142.

d. 0.051)

A ve.uurimeter '" an oil (sp, gr. 11.8) pipe IS COIIIICC~d lo 3 diffeccntial lllaJIOII\eiCr ill which Ote gauge llquod is mercu1v (sp, gr. 13/il. Por ~ flow rate of 11.16 nt1/s. the rnlutonU>ter registers a gnugo ctiffcrenuru of 20 em. TI1c oil -mcJ'CUIY manometer being unava,Jablc. nn air-oil differential manometer as connecte.d to the snme. l'cntun meter. NeglccL111g \ ariat10u of discharge coefficocnt for d10 venl.lllimeteo·. " hal IS IlK' IIC\\ .!f:UJl" diffCICIIIIal for n flm, mte o((UI8 111 Is 'I

a. 64 am

b. 68cm

c 80cm

d. 85 Clll

:How nre the velOCity coefflcienl C.. the discharge coefficient C.s, nnd the contraction coefficient C, of au onfice related~'

a. c •. ; C.C.t

u. c, = c.cd c. C., ; cc.

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•) I.

92.

93.

'14-.

95.

d c.c,c,= 1

Whkh one of the fc•l lcl\1 ing Stfll~lllems i• corrccl • While u$ing boundary lay~r

equations. llcmoulli's equation a, can be used unywhe~ b. can be used only outside 1hc boundary

layer c, can be used only onside the boundary

l•yer d cannul bc used either inside or ouiSJdc

che ooWJdruy layer l'hc vdodt) d L~cributinn in lite boundary l~ycr over a llat plate, ~el parulh:l h i the di•·ect ion <If m1 incornprc~~ible frc~ srreaou ~~ g1wn by t•nc-si~ th pOwer law of tl•~ torm u/U = (y/ll)1A' What is tl1e rat iu of displaccmcnc thicknc.<Q lQ boundar) la)cr chickncss ')

a. I 8 b. I 7

c, 7 : 72

d 3 8

An open channel of symmctnc rig.hl­nngled triangular cross- sectoon is con~eying n dischnrge Q. Taking ).!liS the acc.d eralion due to gruv1ly. ''jhnl is thtJ critical dopth ?

a r~r b. ( 2~· r c. (~ r d (l;'r In M-1.-T ~yslem, whnt ls 01e dimcn<IClll o11' specific ~peed for " mtodynamic pump 7 a. L -ll• rJJl b. M 11: L' 11 r m c. L 1" r~':!

d. L'" r'~

In !he boundary layer. the flmv is a. Vis co us and rotationnl b luviscid tlnd lrmtationul

9b.

97.

98.

99.

c. lnv1scld aud rotational d Vbcous and irrutouionnl

I ~ urt I

II is observed in a flow problem, !hal pressure. inertia and gravity forces are impootmot The•~ similarity r~quires !hat a. Reynold• and Wcb~r numbers b~ cquol b. Mnch ond Froudt numbers be equrol c. Eiuler and Froude numbers be ec1ual d. Reynolds und Much numbers be ~qual In a nor0111l shock in a gas a. Both the: downstream flow and th~

upslrcam llow arc supersonic b. Only lbc upstrcam now is supcrsllnic c. The ilownstream now b sonic d The upstream now is subSfmk Tbe pressuro tlrop fn a pipe now is directly prOfiQI1ionalto the mean ' 'el<>oot,y It c.un be deduced lhat ~~c a. Plow is laminar b Flow is turhulent c. l'ipe is ~~~ •0111h

d. Pipe is rough

+

A circular jet of wnte.r impinges on n vertical Oat plot~ nnd bifurcates into tW<> circular jets of half the dian•ctcr or lht vriginal. ,\ftcr hiuing the plate a. Th~ jets move at ~quul velocity which

is twice ofthe original w locity b. The jets move nl equal velocity which

is J tomes of tl1e original velocity c. Daia given is iosu fficient 10 t:alculatc

velocities of the two outgoingj~ts

d Th~ j~LS mo~c 111 equal 'docity which is equal to chc origonal velocity

I 00. h is recommended that the difl'user aogle shnuld he keplle$5 th:UI I 8° because a. f'rcssuo-.: decreases m now direction

nnd tlo\\ separation may occur

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b. l'res$ure decreases in flow direc-tion and now mny become turbulent

c. PreR§UI'\1 inc-rcnscs 10 flow direction and flow separation m3)' occur

d_. Pre~sure increoses- in tlo.w direcrion and flow may become turbulent

10 I A converging diverging nozzle l. c.mnectcd 10 n gas pipeline. At the. Inlet of tbu nozzl<> (converging •oclion) the Mach number is 2. It is observed that lll<>ro is • shock in the dwergmg section. Wbat is the­vahtt ofUt~ M1ch numb.:r at lite throat ?

a "' I b. EQ11~ltu I

"" ,. 1 d. ~ I

102 Which one of the f<•llt>wing is measured by n r<1l;:J1tieta·?

a ·velocity of Duid~ b. Discharge of Ouids

c. ViscoRity of fluids

d. Rotntiunol speell <1f ~olid •ha (h

103. In o _jet punlp

n. Kin~tic unctgy of Ooid i! couv..,rh;d into potential energy

b. Energy of ltig_h velocity •trc:un ,. converted inlo press ure energy

~. Energy of ltigh prc~ouro Ouio is converted into energy of I0\1 pressure fluid

cl Potenti>l ene111y <>f ll11i<l ,. converted into lOnetic energy

HH Which of the following wnter tmbtnes does not require a draft tube 'I

~- Propeller turbine

b. Pelton turbine

~ KopiM turbine

d. Francis turbine

105. Wbich u( Lh~ following "ater turbiue. 1hni..ntain ~~ ltigh cfficicnc.>' ovcJ .1 long range t)flhe p;o11lnncl 7

I . Fro.nci; tw·bine

2. !Coplon tllJ'bin"

3. Pelton lurbin"

4. Pr~peller turbine

Sole~t the cvrrect ~n~wer u.slng the codes giv~n bclo\1

a. 1 and 4

b. Only 2 and 3

<.:.. L2aud3

d. 2. 3 and 4

13utl4

11>6. Whi"h of the following ~dvantag"" iFiar" tWssessed b)' a KAt)lan turbine: uvcr • lintHt:.IS 1Uf~)inc 'l

1. Low frictiou;ol loss.,s.

2. Pru1. toad effi.,ien~y ;, consideral>ly high.

3. More comp>cl ancJ small or in site.

Select the correct an~wer u•ing th" code. given hcltJW

a. Only I b. Only I and 2

c. Only 2 •ncl3

d. 1, 2attd 3

107. Effectiv.: tempCI'atur.: depends on dJ) bu lb h!mpcraturtj. nod

a. \\lct bulb l<:mp~ralurc only

b. Relauvc humidily

c. Spe<~itle humidity d. Wet bulb temperature nod air motion

108. A humruJ body fcols oomforublo wh.m tho heat produced by U>e metabolism of human body is equal to

a. Heat dissipated to the >!UITOilndings

b. Heat •ttm:d in the hurn!ln bndy

c. Sum of lL ond b.

d. Difference of o. and b.

109. In 4 vapmn Cl)mprcssiun refri!fer:ttion plaJil, tloc cntllnlt>Y values nl tliifl:l'<1ll

pointli are ;

I. Enlhalpy nl exit of !be evoporator • 350 kJI\:g

2. Enthalpy ol oxil of the compressor 375 k.llka

3. l~nUwlpy ~~ exit of the condenser = 225 kJikg

The refrigerating efficiency of the plant i• 0.8. What is the power Te<Jtrired pcr k\\1 of couling to be pruduccd'1

•· o.zs ~w b. ~.O k\

c. 12.5 k\V

d. llk\V

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L 10. Thy bulb lemperoture oml wet bulb temp<.'1'3tllfc is 25•C .:.ch. and velocity ol' Air possing ovor human body i.~ 6 mimi~. II' velocity increase.\ to 20 mimin. tltcn wltich one of l)lc fC>IIowing ill correct?

n, 1l1e effective temper~ture ~ereo.~e• b. The effoolivc tcmpcmtluro remain.; lllo

N3111£f

c. ll1c effective tcmpcr.1turo incl'..:a:u .. "tt

d. Tile cbangc in ~ffcctive temper:•ture C'Jtutot be t>Stimoled wiU1 U1e giveu informntion

Ill. TI1o wet hulh dcprcs~ iun i• zct'O, "hen relxlive humidity i~ e<[U:tllo :

IL Ill()"•

b. 60Uo 1:. 40'' u

d. zer., 112. A.tmosphe~ic •lr ot 3 5"1 • and 60% RH can

be brought lo 20"C ond 60'lu RH by.

a. Cooling • nd dehnmidiiication rrocess

h C<1ol ing and hnmidification proce~s

<:. Adiob~ttic s•tur•tion proc...-u d. Scnsiblo cooling process

113. Consider the followmg stolemenls :

Air w11.~her can wQrk M

I HumidiJier only

2. DohumidiJior only

3. 'Filtc·•· only W11ich of Ute sl:il<>met•IS given Jll(lve islo.re eorrc.:t 1

~. Only I b. Unlv 2 and 3

c_ <)nly I anrl ~

d. 1. 2nnd 3 I 14. For small inslll llntion• of rcfrigcmtion

systems (up to ;.; k\1 ), which type of condenser is used ?

n. Shell •nd lube type

b. Shell ~nd coil type

c. Double tube type

d. Air cool.:d type LJ5. In a vapour absorption refriger.~tor. heal i;

rtjo.oted in :

A. Condenser /lnly

h. Gencmtor only

llntl4 c. Absorber only d. Condcn•er and absorb«

I 16. Wbdrc on nir 1\d'rig~ralion cycle is generally employ•'<!')

~. Domestic rcfiigcr•tor$

b. Commereial reliigcrall>l's

c. ;\j)·...:onditionutg

d. Gas liq11ernction

117. A heaL pump is ~ed co heat • house in the winter tmd then re\'er;;ed to cool the house in the summer. 'lltc in~ide lcmporot11re uf the holL•c j.s lQ be m•intaincd 4L 20•c. 1l1c heat Iran• fer Utr<tugh the hou~e walt. is 7.9 kJis and Ute outside temperature in will!«' is 5"C.

\VhM is the minhnum po1• er (npproximak) required tl.> tlrivc t.ltc he•( pump1

ll, 40.5 '\\'

b. 405 w c. .12.5 \V

d. 4'25 w 118. The 1ew in o refrigerAtion system Fre<>n

are detected by -

a. A halide Lorch, which on do1llcting produces greenish !lame light

b. Sulphur sucks, which on detoc!ing give the smoke

c. l1~ing reagents

d. Sensing reduction in pressures.

I 19. Whul is tlw value of the shape foetor of two inJinne paro.llel s01foce •cparated by a distanced 'I a. ()

b. ,,

c. d. ,,

120 It' the temlferature ot a ~oild siate- change.~ from 17"C to 627"C. then emissive power ch~ngcs. which rat~J a. G . I

b. 9 : I

"- 17 ·I d. ~I : I