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question_answer1) What is a cyclic process? What is the change in internal energy of a system after it completes one cycle of such a process?
question_answer2) State the first law of thermodynamics.
question_answer3) How does the internal energy of an ideal gas differ from that of real gas?
question_answer4) Is the internal energy of a gas a function of pressure? Comment.
question_answer5) Out of a solid, liquid and gas of the same mass and at the same temperature, which one has the greatest internal energy? Which one least? Justify.
question_answer6) When is the heat supplied to a system equal to the increase in its internal energy?
question_answer7) A gas does work during isothermal expansion. What is the source of mechanical energy so produced?
question_answer8) A gas does work during adiabatic expansion. What is the source of mechanical energy so produced?
question_answer9) The temperature of a gas rises during an adiabatic compression, although no heat is given to the gas from outside. Why?
question_answer10) An ideal gas is compressed at constant temperature. Will its internal energy increase or decrease?
question_answer11) Cooling is produced when a gas at high pressure suddenly expands. Why?
question_answer12) When a gas is suddenly compressed, its temperature rises. Why?
question_answer13) If an inflated tyre bursts, the air escaping out is cooled, why?
question_answer14) Is it possible that there is change in temperature of a body without giving heat to it or taking heat from it?
question_answer15) Is it possible that there is no increase in the temperature of a body despite being heated?
question_answer16) Can the temperature of a gas be increased by keeping its pressure and volume constant?
question_answer17) Why does air pressure in a car tyre increase during driving?
question_answer18) Whose molecules: liquid water at \[\mathbf{0}{}^\circ \mathbf{C}\] or ice at \[\mathbf{0}{}^\circ \mathbf{C}\] have greater potential energy? Give reason.
question_answer19) Why mechanical energy can be completely converted into heat energy but the whole of the heat energy cannot be converted into mechanical energy?
question_answer20) During adiabatic changes, the volume of a gas is found to depend inversely on the square of its absolute temperature. Find how its pressure will depend on the absolute temperature.
question_answer21) Does the mass of a body change when it is heated or cooled?
question_answer22) When air of the atmosphere rises up, it cools. Why?
question_answer23) Is the equation \[\mathbf{PV=RT}\] valid for isothermal and adiabatic processes?
question_answer24) If \[\mathbf{PV=RT}\] is valid for all types of thermodynamically processes, what do the relations \[\mathbf{PV = a}\] constant and\[\mathbf{P}{{\mathbf{V}}^{\gamma }}=\text{ }\mathbf{a}\] constant, signify?
question_answer25) First law of thermodynamics does not forbid flow of heat from lower temperature to higher temperature. Comment.
question_answer26) Can two isothermal curves intersect?
question_answer27) What is the significance of the area of closed curve on a \[\mathbf{P}-\mathbf{V}\] diagram?
question_answer28) Can the work done during a cyclic process be zero?
question_answer29) How many specific heats does a gas possess?
question_answer30) Why a gas has two principal specific heat capacities? Or Gases have two specific heats, but the solids and liquids possess only one specific heat. Why?
question_answer31) Compare the formula \[{{\mathbf{C}}_{\mathbf{P}}}\mathbf{ -}{{\mathbf{C}}_{\mathbf{V}}}\mathbf{=R}\] for an ideal gas with the thermodynamic relation \[\Delta U=\Delta Q-P\Delta V.\]
question_answer32) A gas has two principal specific heats. Which one is greater and why?
question_answer33) Of what physical significance is the difference between the two principal specific heat capacities and their ratio?
question_answer34) Can specific heat of a gas be negative?
question_answer35) What is the specific heat of a gas in an isothermal process?
question_answer36) What is the specific heat of a gas in an adiabatic process?
question_answer37) A liquid is being converted into steam at its boiling point. What will be the specific heat of the liquid at this time?
question_answer38) By what methods can the internal energy of an ideal gas be changed? Give examples.
question_answer39) Heat equivalent to 50 joule is supplied to a thermodynamic system and 10 joule work is done on the system. What is the change in the internal energy of the system in the process?
question_answer40) \[\mathbf{400 J}\] of work is done on a gas to reduce its volume by compression adiabatically. What is the change in internal energy of the gas?
question_answer41) An ideal gas is taken around the cycle ABCDA as shown in the \[\mathbf{P-V}\] diagram. What is the work done during the cycle?
question_answer42) What is difference between heat and work?
question_answer43) Why is the conversion of heat into work not possible without sink at lower temperature?
question_answer44) Explain why it is impossible to design a heat engine with 100% efficiency. Or Even Carnot engine cannot have 100% efficiency. Explain, why?
question_answer45) Why can a ship not use the internal energy of sea water to operate its engine?
question_answer46) In a Carnot engine, the temperature of the sink is increased. What will happen to its efficiency?
question_answer47) What is meant by reversible engine? Explain why the efficiency of a reversible engine is maximum?
question_answer48) If you are asked to increase the efficiency of a Carnot engine by increasing the temperature of the source or by decreasing the temperature of the sink by\[\mathbf{10}\text{ }\mathbf{K}\], which method would you prefer and why?
question_answer49) The temperature of the surface of the sun is approximately\[\mathbf{6000}\text{ }\mathbf{K}\]. If we take a big lens and focus the sun rays, can we produce a temperature of\[\mathbf{8000}\text{ }\mathbf{K}\]?
question_answer50) Is the efficiency of a heat engine more in hilly areas than in the plains?
question_answer51) Is it theoretically possible to device a heat engine which will create no thermal pollution?
question_answer52) Can a kitchen be cooled by leaving the door of an electric refrigerator open? Or If a door of a working refrigerator is kept open for a long time in a closed room, will it make the room warm or cool?
question_answer53) How a refrigerator can be used as a heat pump to heat a house in winter?
question_answer54) Milk is poured into a cup of tea and is mixed with a spoon. Is this an example of a reversible process? Give reason.
question_answer55) A system goes from state A to B via two processes \[I\] and \[II\], as shown in Fig. How are \[\Delta {{U}_{1}}\]and \[\Delta {{U}_{2}}\] (the changes in internal energies in the processes \[I\] and \[II\]) related to each other?
question_answer56) A thermos flask contains coffee. It is vigrously shaken. Consider the coffee as the system. (i) Has any heat been added to it? (ii) Has any work been done on it? (iii) Has its internal energy changed? (iv) Does its temperature rise?
question_answer57) When a bore is made with a small drill in a hard board, the drill becomes very hot. But when the bore is made in a soft board, the drill does not become so hot. Why?
question_answer58) What is an isothermal process? What are the essential conditions for an isothermal process to take place?
question_answer59) What is an adiabatic process? What are the essential conditions for an adiabatic process to take place?
question_answer60) Explain why the internal energy of a compressed gas is less than that of a rarefied gas at the same temperature.
question_answer61) When you whistle out air on to your palm held close to your mouth, the air feels cold; but when you blow out air from your mouth, keeping it wide open, the air feels hot. Why?
question_answer62) Two bodies of specific heats \[{{c}_{1}}\,\] and \[{{c}_{2}}\,\] having same heat capacities are combined to form a single composite body. What is the specific heat of the composite body?
question_answer63) A gas expands in such a manner that its pressure and volume comply with the condition \[\mathbf{P}{{\mathbf{V}}^{\mathbf{2}}}\mathbf{=}\]constant. Will the gas cool or get heated on expansion?
question_answer64) What happens to the change in internal energy of a gas during (i) isothermal expansion and (ii) adiabatic expansion?
question_answer65) Show that the slope of an adiabatic curve at any point is y times the slope of an isothermal curve at the corresponding point.
question_answer66) The volume versus temperature T graphs for a certain amount of a perfect gas at two pressures \[{{P}_{1}}\] and \[{{P}_{2}}\] are shown in Fig. Which one is greater - \[{{P}_{1}}\]or \[{{P}_{2}}\]?
question_answer67) In Figs. (a), (b) and (c) given below, identify the isothermal and adiabatic process in each diagram.
question_answer68) No real engine can have an efficiency greater than that of a Carnot engine working between the same two temperatures. Give reason.
question_answer69) Can a Carnot engine be realised in practice?
question_answer70) The volume of an ideal gas is V at pressure P. On increasing the pressure by \[\Delta P\], the change in volume of the gas is \[\Delta {{V}_{1}}\] under isothermal conditions and \[\Delta {{V}_{2}}\] under adiabatic conditions. Under which of the two conditions, will the change in volume be more? Given reason.
question_answer71) Discuss whether the following phenomena are reversible : (i) Water fall (ii) Rusting of iron (iii) Electrolysis.
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