1. What is the diference between isotropic and anisotropic materials ?
Ans: I a material exhibits same mechanical properties regardless o loading direction, directio n, it is isotropic, e.g., homogeneous cast materials. Materials lacing this propert! are anisotropic. ". What are orthotropic materials ? Ans: It is a special class o anisotropic materials which can be described b! gi#ing their prop$erties in three perpendicular directions e.g. wood% composites. &. What is #iew actor ? Ans: 'iew actor is dependent upon geometr! o the two suraces exchanging radiation. (. What properties need to be considered or applications calling or ollowing re$)uirements : *i+ rigidit! *ii+ strength or no plastic deormation under static load *iii+ strength to withstand o#erload without racture. *i#+ wear resistance *#+ reliabilit! and saet!. Ans: *i+ igidit!-lastic modulus and !ield strength *ii+ /trength *or no plastic deormation under static loading+-!ield point *iii+ /trength *o#erload+-0oughness and impact resistance *i#+ Wear resistance-ardness *#+ eliabilit! and saet!-ndurance limit and !ield point. 2. xplain the efects o allo!ing chromium and nicel in stainless steel. Ans: Addition o nicel and chromium increases the tensile strength and increase in resistance to corrosion taes place. 3. Mention two t!pes o dislocations. Ans: 4islocation reers reers to a brea in the continuit! o the lattice. In edge dislocation, one plane o atoms gets s)uee5ed out. In screw dislocation dislocation the lattice atoms mo#e om their regular ideal positions. 6. What are the principal constituents o brass? Ans: 7rincipal constituents o brass are copper and 5inc. 8. What is 9urie point ? Ans: 9urie point is the temperature at which erromagnetic materials can no longer be magnetised b! outside orces. . /peci;c strength o materials is #er! high when the! are in ;bre si5e but lower when the! are in bar orm Wh! ?
Ans: 9r!stal structure has ordered, repeating arrangement o atoms. <ibres are liable to maintain this and thus ha#e high speci;c strength. As si5e increases, the condition o ordered and repeating arrangements can=t be guaranteed because o se#eral t!pes o deects and dislocations and thus the speci;c strength gets lower. 1>. What is the percentage o carbon in cast iron ? Ans: ".2. 11. Which element is added in steel to increase resistance to corrosion ? Ans: 9hromium. 1". Whether indi#idual components in composite materials retain their characteristics characteris tics or not? Ans: !es. 1&. An elastomer elastomer is a pol!mer when its percentage percentage elongation rate is ? Ans: @reater than 1>>. 1(. I percentage elongation o a material is more more than ">>, it is classed as ? Ans: ubber. 12. Wh! is it that the maximum #alue which the residual stress can reach is the elastic limit o the material ? Ans: A stress in excess o elastic limit, with no external orce to oppose it, will relie#e itsel b! plastic deormation until it reaches the #alue o the !ield stress. 13. Wh! atigue strength decreases as si5e o a part increases be!ond around 1> mm? Ans: 7erection o material conditions is possible at lower si5es and as si5e increases, it is not possible to attain uniorm structure o the material. 16. 4istinguish between creep and atigue. Ans: 9reep is low and progressi#e deormation o a material with time under a constant stress at high temperature applications. <atigue is the reduced tendenc! o material to ofer resistance to applied stress under repeated or uctuating loading condition. 18. While normal carburising and nitriding surace treatments increase atigue strength, excessi#e treatment ma! decrease the atigue strength. Wh! ? .Ans: Bormal carburisingCnitriding treatments increase #olume due to phase transormation at /urace and introduce residual compressi#e surace stress and thus increase the atigue strength. D! excessi#e treatment the high compressi#e stresses are and introduced but these are balanced b! high in$ternal stresses e)ual #alue the subsurace atigue cracs ma! de#elop in thetensile regions o higho
tensile stress and lead to earl! atigue ailure. 1. Eist at least two actors that promote transition rom ductile to brittle racture. Ans: Manner o loading, and the rate o loading promote transition rom ductile to brittle rac$ture. A machine member ma! ha#e ductile ailure under static loading but ma! ail in brittle ashion when the load is uctuating. /imilarl! a material ma! e#idence ductile ailure under tensile loading at ordinar! testing speed but i load is applied at a high #elocit! then ailure ma! be brittle. ">. Whic Which h theories theories o ailur ailure e are are used or *a+ *a+ ductil ductile e material materials, s, and and * brittle brittle materials ? Ans: <or ductile materials, theories o ailure used are maximum shear stress theor!, and maximum energ! o distortion theor!% while or brittle materials, theor! o maximum principal stress, and maximum strain are used. "1. What does thermal difusi#it! o metals signi!. Ans: 0hermal difusi#it! is associated with the speed o propagation o heat into solids during changes in temperature with time. "". <or conduction o heat, the instantaneous rate o heat ow is product o three actors. What are these ? Ans: *i+ Area o the section o the heat ow path, perpendicular to the direction o heat ow. *ii+ temperature gradient, i.e. change o temperature w.r.t. length o path. *ii+ 0hermal conducti#it! o material. "&. ow con#ecti#e heat transer is efected and on what actors it depends ? Ans: 9on#ecti#e heat transer is efected between a solid and uid b! a combination o molecular conduction within the uid in combination with energ! transport resulting resultin g rom the motion o uid particles. It depends on boundar! la!er con;guration, uid properties and temperature diference. "(. Which is the common element between brass and bron5e bron5e ? Ans: 9opper 9 opper.. "2. What does ollowing allo! designation indicate <@ "2> ? Ans: @re! cast iron with tensile strength o "2> M7a. "3. ow is ceramic de;ned ? Ans: It is a solid ormed b! combination o metallic and nonFmetallic elements. "6. @i#e one example o metal classi;ed as per structure as D99, <99, 97 and 997. Ans:
<99 *ace centred cubic+ structure-Aluminium 97 *hexagonal closed paced+ structure-Ginc 997 *cubic dosed paced+ structureF9opper. "8. What is the name o solid solution o carbon in alpha iron and delta iron ? Ans: <errite and austenite respecti#el!. ". xplain the diference between pearlite and cementile ? Ans: 7earlite is eutectoid mixture o errite and cementile. 9ementite is chemical compound o iron and carbon. &>. @i#e one example each o the ollowing proportion proportion o materials dimensional, ph!sical, technological and mechanical. Ans: oughness, enthalp!, toughness, and hardness respecti#el!. &1. <or which parts the Wahl actor and Eewis orm actor used ? Ans: <or springs and gears respecti#el!. &". ow ox!gen can be remo#ed rom steel during melting? What are ull! illed steels ? Ans: Hx!gen can be remo#ed b! adding elements such as manganese, silicon or aluminium which, because o their high anit! or ox!gen, react with it to orm nonF metallic oxides which rise into the slag. /teels which ha#e had most o their dissol#ed ox!gen remo#ed are called Jull! illed steelsJ. &&. !drogen cannot be remo#ed easil! rom molten steel. What harm h!drogen has on propert! o steel ? Ans: xecessi#e h!drogen results in the ormation o small ;ssures oten described as hairline cracs or aes in the steel. Earge orgings in allo! steel are particularl! sensiti#e to this phenom$enon. &(. What is allotrope ? In what orms o cubic pattern, iron exists ? Ans: /ome elements exist in more than one cr!stalline orm. ach orm is nown as JallotropeJ. Iron exists in two orms o cubic pattern, namel! bod! centered cubic *bcc+ and aceFcentered cubic *ee+. &2. What is the diference between alpha iron, delta iron and gamma iron ? Ans: 0he bcc orm o iron exists between room temperature and 1>K9, and between 1(>>K9 and the melting point at 12&K9. 0he lower temperature orm is nown as JalphaJFiron and the higher temperature orm as JdeltaJFiron. 0he aceF centered cubic orm existing between 1>K9 and 1(>>K9 is reerred to as JgammaF ironJ. &3. Metals, in general are o low strength and do not possess re)uired ph!sioF
chemical and technological properties or a de;nite purpose. Allo!s are thereore more than metals alone. 4iscuss the arrangement o atoms and structures o allo!s. Ans: Allo!s are produced b! melting or sintering two ore more metals, or metals and a nonFmetal, together. Allo!s possess t!pical properties inherent in the metallic state. 0he chemical elements that mae up an allo! are called its components. An allo! can consist o two or more components. 0he phase and structures o allo!s describe the constitution, transormations and properties o metals and allo!s. A combination o phases in a state o e)uilibrium e)uilibrium is called a s!stem. A phase is a homogeneous portion portion o a s!stem ha#ing the same composition and the same state o aggregation throughout its #olume, and separated rom the other portions o the s!stem b! interaces. <or instance, a homogeneous pure metal or allo! is a singleF phase s!stem. A state in which a li)uid allo! *or metal+ coexists with its cr!stals is a twoFphase s!stem. /tructure reers to the shape, si5e or the mutual arrangement o the corresponding phases in metals or allo!s. 0he structural components o an allo! are its indi#idual portions, each ha#ing a single structure with its characteristic eatures. &6. What is the diference between isotropic material and homogeneous material ? Ans: In homogeneous material the composition is same throughout and in isotropic material the elastic constants are same in all directions. &8. xplain the diference between the points o inexion and contraexure. Ans: At points o inexion in a loaded beam the bending moment is 5ero and at points o contraexure in loaded beam the bending moment changes sign rom increasing to decreasing. &. What is the diference between proo resilience and modulus o resilience ? Ans: 7roo resilience is the maximum strain energ! that can be stored in a material without permanent deormation. deormation. Modulus o resilience is the maximum strain energ! stored stored in a material per unit #olume. (>. What is the diference between column and strut ? Ans: Doth column and strut carr! compressi#e load. 9olumn is alwa!s #ertical but strut as member o structure could carr! axial compressi#e load in an! direction. (1. xplain the diference diference between errite, austenite and graphite ? Ans: <errite is the solid solution o carbon and other constituents in alphaFiron. It is sot, ductile and relati#el! wea. Austenite is the solid solution o carbon and other constituents in gammaFiron. It exists in ordinar! steels at ele#ated temperatures, but it is also ound at ordinar! temperatures in some stainless steels. @raphite has a hexagonal la!er lattice. = (". xplain the terms solid solution, eutectic, eutectoid and peritectic.
Ans: /olid /olution. When a homogeneous mixture o two *or more+ atomic orms exists in solid state, it is nown as solid solution. utectic. A mixture o two *or more+ phases which solidi! simultaneousl! rom the li)uid al$lo! is called an eutectic. Allo!s in which the components solidi! solidi! simultaneousl! simultaneous l! at a constant tem$perature the lowest or the gi#en s!stem, a are re called eutectic allo!s. utectoid. utectoid allo!s are the allo!s or which two solid phases which are completel! soluble become completel! insoluble on cooling beore a certain temperature temperatur e called eutectoid tem$perature. tem$perature. 7eritectic. A peritectic transormation in#ol#es a reaction between a solid and li)uid that orm a diferent and new solid phase. 0his three phase transormation occurs at a point called peritectic point. (&. What do !ou understand b! critical points in iron, ironFcarbide diagram ? Ans: 0he temperatures at which the phase changes occur are called critical points *or tem$peratures+. (2. Wh! 70 is preerred o#er 97M or e#aluation o proLect ? Ans: 70 is based on the approach o multiple time estimates or each acti#it!. (3. What is the percentage o chromium chromium in 18 : ( : 1 II// ? Ans: (. (6. What is stellite ? Ans: It is a nonFerrous cast allo! containing cobalt, chromium and tungsten. (8. Which ra!s are produced b! cobaltF3> in industrial radiograph! ? Ans: @amma ra!s. (. What are illed steels and what or these are used ? Ans: illed steels are deoxidised in the ladle with silicon and aluminium. Hn solidi;cation no gas e#olution occurs in these steels because the! are ree rom ox!gen. 2>. What is critical temperature in metals ? Ans: It is the temperature temperature at which the phase change occurs in metals. 21. 9ar t!res are usuall! made o ? Ans: /t!reneFbutadine rubber. 2". What is the structure o pure iron and whether it is sot or hard ? Ans: <errite and it is sot. 2&. Which elements increase the corrosion resistance o steel ?
Ans: 9hromium and nicel. 2(. What causes hardness in steel ? ow heat treatment alters properties o steel ? Ans: 0he shape and distribution o the carbides in the iron determines the hardness o the steel. 9arbides can be dissol#ed in austenite is the basis o the heat treatment o steel. I steel is heated abo#e the A critical temperature to dissol#e all the carbides, and then cooled, suitable cooling through the cooling range will produce the desired si5e and distribution o carbides in the errite, imparting diferent properties. 22. xplain the ormation o microstructures o pearlite, bainite and martensite in steel. Ans: I austenite containing about >.8> percent carbon is slowl! cooled through the critical temperature, errite and cementite are reLected simultaneousl!, orming alternate plates or lamellae. 0his microstructure is called pearlite. At temperatures Lust belot the the A1, the transormation transormation rom rom austenite.to austenite.to pearlite ma! tae tae an appreciable apprecia ble time to initiate and complete, but the product will be lameller pearlite. As the transormation temperature is lowered, the time to initiate transormation shortens but the product is pearlite o increasing ;neness, and at temperatures approaching 22>K9 it cannot be resol#ed into its lamellar constituents. <urther deerease in transormation temperature causes a lengthening o the ncubation period and a change in structure o the product to a orm nown as JbainiteJ. I the temperature is lowered sucientl!, the difusion controlled nucleation and growth modes o transormation are suppressed completel! and the austenite transorms transor ms b! a difusionless process in which the cr!stal lattice efecti#el! shears to a new cr!stallographic con;guration con;guration nown as JmartensiteJ. 0his phase has a tetragonal cr!stal structure and contains carbon in supersaturated solid solution. 23. ow with allo!ing o steel it is possible to a achie#e proper properties ties which can not be achie#ed with heat treatment ? Ans: A prere)uisite the hardening o steels thato martensite be ormed on cooling, but this to can onl! be achie#ed i theisrate cooling is should great enough to suppress the ormation o pearlite or bainite and in plain carbon steels this can be achie#ed b! )uenching relati#el! relati#el! small specimens 26. What are the maLor efects o allo!ing elements? Ans: *1+ 0o alter the transormation temperatures and times *"+ 0o modi! the room temperature temperat ure and ele#ated ele#ate d temperature temperatu re strengths o gi#en structures structur es b! *a+ *a+ stifen stifening ing the the cr!sta cr!stals ls and and * introduc introducing ing comple complex x precip precipitate itates s which tend to harden the steel. *&+ 0o modi! the t!pe o oxide oxide ;lm ormed on the surace o the steel and thereb! afect its corrosion resistance.
28. What is the diference between austenite stabilisers and errite stabilisers ? Ans: Austenite stabilisers ha#e the efect o extending the temperature range o#erwhich austenite is ormed. /uch elements are carbon, manganese, nicel, copper and cobalt. <errite stabilisers ha#e the efect o extending the temperature range o#er which alpha and delta errite are ormed, which conse)uentl! reduces temperature range o#er which austenite is ormed. /uch elements are silicon, chromium, mol!bdenum, tungsten, titanium and niobium. 2. What are the efects o carbon on the properties o steel. Ans: In general, an increase in carbon content produces higher ultimate strength and hardness but lowers ductilit! and toughness o steel allo!s. 9arbon also increases airFhardening tendencies and weld hardness, especiall! in the presence o chromium. In lowFallo! steel or highFtemperature highFtemperature applications, the carbon content is usuall! restricted to a maximum o about >.12 in order to assure optimum ductilit! or welding, expanding, and bending operations. 0o minimi5e intergranular corro$sion caused b! carbide precipitation, the carbon content o austenitic *18F8 t!pe+ allo!s is limited in commercial speci;cations to a maximum o >.>8, or e#en less, i.e. >.>& in the extremel! lowFcarbon grades used in certain corrosionF resistant applications. In plain carbon steels in the normalised condition, the resistance to creep at temperatures below ((>K9 appears to increase with carbon content up to >.( carbon, at higher temperatures there is but little #ariation o creep properties with carbon content. An increase in carbon content lessens the thermal and electrical conducti#ities o steel and increases its hardness on )uenching. 3>. What is the role o silicon as allo!ing element in steels ? Ans: /ilicon contributes greatl! to the production o sound steel because o its deoxidi5ing and degasi!ing properties. When added in amounts up to ".2, the ultimate strength o the steel is amounts increasedhigher without loss2 in ductilit!. in excess o ".2 causes brittleness, and than mae the/ilicon steel nonF malleable. esistance to oxidation and surace stabilit! o steel are increased b! the addition o silicon. 0hese desirable efects partiall! compensate or the tendenc! o silicon to lower the creep properties o steel. /ilicon increases the electrical resisti#it! o steel and decreases h!steresis losses. 31. 4iscuss the role o manganese in allo!ing steels. Ans: Manganese is an excellent deoxidi5er and sulur neutrali5er, and impro#es the mechanical properties o steel, notabl! the ratio o !ield strength to tensile strength at normal temperatures. As an allo!ing element, manganese ser#es as an inexpensi#e means o pre#enting Jhot owe#er shortnessJ. It impro#es rolling properties, hardenabilit!, and resistance to wear. manganese increases the crac
sensiti#it! o weldments, particularl! with steels o higher carbon content. 3". 4e;ne bucling actor. Ans: It is the ratio o the e)ui#alent length o column to the minimum radius o g!ration. 3&. What do !ou understand b! catenar! cable ? Ans: A cable attached to the supports and carr!ing its own weight. 3(. What is coaxing ? Ans: It is the process o impro#ing atigue properties b! ;rst underFstressing and then increasing the stress in small increments. 32. What is diference between conLugate beam and continuous beam ? Ans: A conLugate beam is an imaginar! beam o same si5e as original beam and carr!ing a distributed load in accordance with the bending moment diagram. A continuous beam is one which is resting on more than two supports. 33. What is isotropic material ? Ans: It is a material ha#ing same elastic constants in all directions. 36. xplain diference between modulus o resilience and modulus o rigidit! ? Ans: Modulus o resilience is the maximum strain energ! stored in a material per unit #olume and modulus o rigidit! is the ratio o shearing stress to the shearing strain within the elastic limit. 38. What is the diference between basic hole and basic shat ? Ans: A basic hole is one whose lower de#iation is 5ero and in case o basic shat the upper de#iation is 5ero. 3. or p!ranometer used Ans:What It is used to measure is the total? hemispherical solar radiation. 6>. 4escribe transer machines in brie. Ans: It is an automatic machine in which worpiece alongwith ;xture is transerred rom one station to other automaticall! and se#eral operation on worpiece are perormed at each station. 61. What is burntFout point ? Ans: It corresponds to maximum heat ux at which transition occurs rom nucleate boiling to ;lm boiling. 6". do !ou understand ? Ans:What It is mechanical mixture b! o eutectic two or more phases which solidi! simultaneousl!
rom the li)uid allo!. 6". xplain the diference between gre! iron and white iron. What is mottled iron ? Ans: 0he carbon in cast iron could exist at room temperature as either iron carbide, or as graphite which is the more stable orm. Irons containing carbon as graphite are sot, easil! machinable and are called Jgre! ironsJ. Irons with carbon present as iron carbide are extremel! hard, dicult to machine and are called JwhiteJ irons. Irons with airl! e)ual proportions o graphite and iron carbide ha#e intermediate hardness and are called JmottledJ irons. 6&. 0he graphite in gre! irons exists in the orm o aes which act as stressFraisers under tensile loading and conse)uentl! gre! irons ha#e relati#el! low tensile strength and ductilit!. /till gre! iron is extensi#el! used in engineering. Wh! ? Ans: @re! iron is extensi#el! used in engineering because o ollowing characteristics. *a+ 9heapness. * Eow melting melting point point and high uidit! uidit! maing maing it suitable suitable or castings castings o intricate intricate shape. N elati#el! good erosion and corrosion resistance. *d+ igh damping capacit!, with respect to #ibration. *e+ elati#el! good mechanical mechanica l properties under compressi#e loading. 6(. Onder what condition a con#ergent di#ergent no55le re)uired ? Ans: When pressure ratio is greater than critical pressure ratio. 62. What is endurance limit and what is its #alue or steel ? Ans: ndurance limit is the maximum le#el o uctuating str stress ess which can be tolerated inde;nitel!. In most steels this stress is approximatel! 2> o the ultimate tensile strength and it is de;ned as the stress which can be endured or ten million re#ersals o stress. 63. ow the net wor to dri#e a compressor and its #olumetric ecienc! beha#e with increase in clearance #olume ? Ans: Wor remains unaltered and #olumetric ecienc! decreases. 66. What do !ou understand b! sulphur print ? Ans: /ulphides, when attached with dilute acid, e#ol#e h!drogen sulphide gas which stains bromide paper and thereore can be readil! detected in ordinar! steels and cast irons. While sulphur is not alwa!s as harmul as is sometimes supposed, a sulphur print is a read! guide to the distribution o segregated impurities in general. 68. What is the diferent between brass and bron5e ? Ans: Drass is an allo! o copper with 5inc% and bron5e is allo! o copper with tin.
6. What is the efect o addition o 5inc in copper? What is the use o 6>C&> brass ? Ans: D! addition o 5inc in copper, both tensile strength and elongation increases. 0he 6>C&> brass brass has ex excellent cellent deep drawing drawing propert! propert! and is used used or maing maing radiator ;ns. 8>, What or admiralit! brass used ? Ans: Admiralit! brass with " 5inc and 1 tin has good corrosion resistance and is used or condenser and eed heater tubes. Aluminium is also added to brass to impro#e corrosion resistance. 81. What is the maximum use o magnesium ? Ans: Magnesium is used to allo! with aluminium and as an additi#e or maing /@ */pheroidal @raphite+ iron. 8". What or 5inc ;nds applications ? Ans: @al#ani5ing consumes the largest proportion o 5inc. Ginc is resistant to corrosion but is attaced b! acids and alalies. Ginc allo!.s are suited or maing die casting since the melting point is reasonabl! low. 8&. Which actors inuence the t!pe o racture in ailure o a material ? Ans: /e#en actors inuencing t!pe o ailure are : *i+ 0!pe o material *inherent structure properties+, *ii+ Manner o loading */tatic #ersus d!namic+, *iii+ ange o imposed stress, *i#+ /train rate *static, d!namic, impact+, *#+ /tress distribution *discontinuit! in materialCshape+, *#i+ temperature, and *#ii+ surace treatment. 8(. What is the name gi#en to ratio o actual c!cle ecienc! and ideal c!cle ecienc!. Ans: cienc! ratio. 82. Eist two efects o manganese in plain carbon steels. , Ans: Manganese increases tensile strength and hardness. It decreases weldabilit!. 83. Bame the strongest and weaest t!pe o atomic bonds. Ans: Metallic bond is strongest and molecular bond also nown as 'ander Waals bond is weaest. 86. In which process internal energ! remains constant ? Ans: Isothermal process.
88. What is temper embrittlement in allo! steels and what are its efects ? Ans: mbrittlement attac is usuall! intergranular in metals, i.e. cracs progress between the grains o the pol!cr!stalline material. It imparts a tendenc! to ail under a static load ater a gi#en period o time in those allo! steels which are susceptible to embrittlement. 8. What are whisers ? Ans: Whisers are #er! small cr!stals which are #irtuall! ree rom imperections and dislocations. >. What is Dauschinger efect ? Ans: According to Dauschinger, the limit o proportionalit! o material does not remain constant but #aries according to the direction o stress under c!clic stresses. 1. What is the diference between heat capacit! and speci;c heat o a material ? Ans: 0he heat capacit! o a material is the amount o heat transormed to raise unit mass o a material 1 degree in temperature. 0he speci;c heat heat o a material is the ratio o o the amount o heat transer transerred red to raise unit mass o a material 1 degree in temperature to that re)uired to raise unit mass o water 1 degree o temperature at some speci;ed temperature. <or most engineering purposes, purposes, heat capacities ma! be assumed numericall! e)ual to%speci;c heats. ". xplain the rule to ;nd speci;c heat o a)ueous solutions. Ans: <or a)ueous solutions solutions o salts, the speci;c heat can be estimated b! assuming the speci;c heat o the solution e)ual to that o the water alone. 0hus, or a 12 b! weight solution o sodium chloride in water, the speci;c heat would be approximatel! >.82. &. What do !ou understand b! latent heat ? @i#e our examples o latent heats. Ans: <or pure substances, the heat efects in state at constant pressure *no temperature changeaccompan!ing being e#ident+changes are nown as latent heats. xamples o latent heats are : heat o usion, #aporisation, sublim sublimation, ation, and change in cr!stal orm. (. 4e;ne the terms ree energ! and ree enthalp!. What is their signi;cance and importance ? Ans: <ree energ! *or elmholt5 unction+ is de;ned asCP u F0s. It is e)ual to the wor during a constantF#olume isothermal re#ersible nonow process. <ree enthalp! *or @ibbs unction+ is de;ned as g P h F 0s *where u P internal energ!, h P enthalp!, 0 P temperature, s P entrop!+ @ibbs unction is o particular importance in processes where chemical changes occur. <or re#ersible isothermal stead!Fow processes or or re#ersible constantF
pressure isothermal nonow processes, change in ree energ! is e)ual to net wor. 2.Which parameter remains constant in isochoric process ? Ans: 'olume. 3. What is pol!tropic process ? Onder what conditions it approaches isobaric, isothermal, and isometric process ? In which re#ersible process no wor is done ? Ans: A pol!tropic process is one that ollows the e)uation pun P constant *index n ma! ha#e #alues rom F oc to Q oo. 0his process approaches isobaric when n P >, isothermal when n P 1, and isometric when n P RxS. Bo wor is done in isometric process. 6. Whether superheated steam can be treated lie ideal gas ? Ans: Tes. 8. Hut o constant pressure and constant #olume lines on 0/ diagram which line has higher slope ? And whether slope is constant or #ariable ? Ans: 9onstant #olume line. /lope is #ariable. . Whether entrop! is intensi#e propert! or extensi#e propert! ? Ans: ntrop! is extensi#e propert!. 1>>. In which process uid expands but does no wor ? Ans: 0hrottling process.