JEE Main & Advanced Physics Thermodynamical Processes Question Bank

done Heat Engine Refrigerator and Second Law of Thermodynamics Total Questions - 34

• question_answer1)
  A Carnot engine working between \[300\,K\] and 600K has work output of 800 J per cycle. What is amount of heat energy supplied to the engine from source per cycle [DPMT 1999; Pb. PMT 2002, 05; Kerala PMT 2004]
  A)
             1800 J/cycle                           done clear
  B)
             1000 J/cycle done clear
  C)
             2000 J/cycle                           done clear
  D)
             1600 J/cycle done clear
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• question_answer2)
  The coefficient of performance of a Carnot refrigerator working between \[{{30}^{o}}C\]and \[{{0}^{o}}C\] is                    [UPSEAT 2002]
  A)
             10   done clear
  B)
             1 done clear
  C)
             9     done clear
  D)
             0 done clear
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• question_answer3)
  If the door of a refrigerator is kept open, then which of the following is true [DPMT 2001; BHU 2001; JIPMER 2002; AIEEE 2002; CPMT 2003]
  A)
             Room is cooled                    done clear
  B)
             Room is heated done clear
  C)
             Room is either cooled or heated done clear
  D)
             Room is neither cooled nor heated done clear
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• question_answer4)
   In a cyclic process, the internal energy of the gas
  A)
             Increases                                done clear
  B)
             Decreases done clear
  C)
             Remains constant               done clear
  D)
             Becomes zero done clear
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• question_answer5)
  Irreversible process is
  A)
             Adiabatic process done clear
  B)
             Joule-Thomson expansion done clear
  C)
             Ideal isothermal process done clear
  D)
             None of the above done clear
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• question_answer6)
  For a reversible process, necessary condition is
  A)
             In the whole cycle of the system, the loss of any type of heat energy should be zero done clear
  B)
             That the process should be too fast done clear
  C)
             That the process should be slow so that the working substance should remain in thermal and mechanical equilibrium with the surroundings done clear
  D)
             The loss of energy should be zero and it should be quasistatic done clear
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• question_answer7)
  In a cyclic process, work done by the system is  [BHU 2002]
  A)
             Zero done clear
  B)
             Equal to heat given to the system done clear
  C)
             More than the heat given to system done clear
  D)
             Independent of heat given to the system done clear
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• question_answer8)
  An ideal gas heat engine operates in a Carnot's cycle between \[{{227}^{o}}C\] and \[{{127}^{o}}C\]. It absorbs 6 × 104 J at high temperature. The amount of heat converted into work is .... [KCET 2004]
  A)
             \[4.8\times {{10}^{4}}\,J\]      done clear
  B)
             \[3.5\times {{10}^{4}}\,J\] done clear
  C)
             \[1.6\times {{10}^{4}}\,J\]      done clear
  D)
             \[1.2\times {{10}^{4}}\,J\] done clear
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• question_answer9)
  An ideal heat engine exhausting heat at \[{{77}^{o}}C\] is to have a 30% efficiency. It must take heat at                 [BCECE 2004]
  A)
             \[{{127}^{o}}C\]                   done clear
  B)
             \[{{227}^{o}}C\] done clear
  C)
             \[{{327}^{o}}C\]                   done clear
  D)
              \[{{673}^{o}}C\] done clear
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• question_answer10)
  Efficiency of Carnot engine is 100% if                 [Pb. PET 2000]
  A)
             \[{{T}_{2}}=273\,\,K\]       done clear
  B)
             \[{{T}_{2}}=0\,\,K\] done clear
  C)
             \[{{T}_{1}}=273\,\,K\]       done clear
  D)
             \[{{T}_{1}}=0\,\,K\] done clear
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• question_answer11)
  A Carnot's engine used first an ideal monoatomic gas then an ideal diatomic gas. If the source and sink temperature are \[{{411}^{o}}C\] and \[{{69}^{o}}C\] respectively and the engine extracts 1000 J of heat in each cycle, then area enclosed by the PV diagram is                               [Pb. PET 2002]
  A)
             100 J                                         done clear
  B)
             300 J done clear
  C)
             500 J                                         done clear
  D)
             700 J done clear
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• question_answer12)
  A Carnot engine absorbs an amount Q of heat from a reservoir at an abosolute temperature T and rejects heat to a sink at a temperature of T/3. The amount of heat rejected is [UPSEAT 2004]
  A)
             Q / 4                                         done clear
  B)
             Q / 3 done clear
  C)
             Q / 2                                         done clear
  D)
             2Q / 3 done clear
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• question_answer13)
  The temperature of sink of Carnot engine is \[{{27}^{o}}C\]. Efficiency of engine is 25%. Then temperature of source is [DCE 2002; CPMT 2002]
  A)
             \[{{227}^{o}}C\]                   done clear
  B)
             \[{{327}^{o}}C\] done clear
  C)
             \[{{127}^{o}}C\]                   done clear
  D)
             \[{{27}^{o}}C\] done clear
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• question_answer14)
  The temperature of reservoir of Carnot's engine operating with an efficiency of 70% is 1000K. The temperature of its sink is                                                          [DCE 2003]
  A)
             300 K                                        done clear
  B)
             400 K done clear
  C)
             500 K                                        done clear
  D)
             700 K done clear
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• question_answer15)
  In a Carnot engine, when \[{{T}_{2}}={{0}^{o}}C\] and \[{{T}_{1}}={{200}^{o}}C,\] its efficiency is \[{{\eta }_{1}}\]and when \[{{T}_{1}}=0{{\,}^{o}}C\] and \[{{T}_{2}}=-200{{\,}^{o}}C\], Its efficiency is \[{{\eta }_{2}}\], then what is \[{{\eta }_{1}}/{{\eta }_{2}}\]                    [DCE 2004]
  A)
             0.577                                        done clear
  B)
             0.733 done clear
  C)
             0.638                                        done clear
  D)
             Cannot be calculated done clear
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• question_answer16)
  The efficiency of Carnot's engine operating between reservoirs, maintained at temperatures \[{{27}^{o}}C\] and \[-{{123}^{o}}C,\] is                                    [DPMT 2002, 03; BVP 2004]
  A)
             50%                                           done clear
  B)
             24% done clear
  C)
             0.75%                                       done clear
  D)
             0.4% done clear
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• question_answer17)
  A Carnot engine operates between \[{{227}^{o}}C\] and \[{{27}^{o}}C.\] Efficiency of the engine will be               [DCE 1999; BHU 2004]
  A)
             \[\frac{1}{3}\]                       done clear
  B)
             \[\frac{2}{5}\] done clear
  C)
             \[\frac{3}{4}\]                       done clear
  D)
             \[\frac{3}{5}\] done clear
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• question_answer18)
  A measure of the degree of disorder of a system is known as [Pb. PET 1997; MH CET 1999]
  A)
             Isobaric                                   done clear
  B)
             Isotropy done clear
  C)
             Enthalpy                                 done clear
  D)
             Entropy done clear
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• question_answer19)
  A carnot engine has the same efficiency between  800 K to 500 K and x K to 600 K. The value of x is [Pb. PMT 1996; CPMT 1996]
  A)
                                                       1000 K                                      done clear
  B)
             960 K done clear
  C)
             846 K                                        done clear
  D)
             754 K done clear
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• question_answer20)
  A scientist says that the efficiency of his heat engine which operates at source temperature 127°C and sink temperature 27°C is 26%, then                         [CBSE PMT 2001]
  A)
             It is impossible                     done clear
  B)
             It is possible but less probable done clear
  C)
             It is quite probable done clear
  D)
             Data are incomplete    done clear
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• question_answer21)
  A Carnot?s engine is made to work between 200°C and 0°C first and then between 0°C and ?200°C. The ratio of efficiencies of the engine in the two cases is      [KCET 2002]
  A)
             1.73 : 1                                     done clear
  B)
             1 : 1.73 done clear
  C)
             1 : 1                                           done clear
  D)
             1 : 2 done clear
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• question_answer22)
  Efficiency of a Carnot engine is 50% when temperature of outlet is 500 K. In order to increase efficiency up to 60% keeping temperature of intake the same what is temperature of outlet                [CBSE PMT 2002]
  A)
             200 K                                        done clear
  B)
             400 K done clear
  C)
             600 K                                        done clear
  D)
             800 K done clear
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• question_answer23)
  Even Carnot engine cannot give 100% efficiency because we cannot       [AIEEE 2002]
  A)
             Prevent radiation done clear
  B)
             Find ideal sources done clear
  C)
             Reach absolute zero temperature done clear
  D)
             Eliminate friction done clear
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• question_answer24)
  ?Heat cannot by itself flow from a body at lower temperature to a body at higher temperature? is a statement or consequence of                          [AIEEE 2003, EAMCET (Med.) 2003]
  A)
             Second law of thermodynamics done clear
  B)
             Conservation of momentum done clear
  C)
             Conservation of mass done clear
  D)
             First law of thermodynamics done clear
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• question_answer25)
  A Carnot engine takes \[3\times {{10}^{6}}\,cal\]. of heat from a reservoir at 627°C, and gives it to a sink at 27°C. The work done by the engine is                                       [AIEEE 2003]
  A)
             \[4.2\times {{10}^{6}}J\]  done clear
  B)
             \[8.4\times {{10}^{6}}J\] done clear
  C)
             \[16.8\times {{10}^{6}}J\]       done clear
  D)
             Zero done clear
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• question_answer26)
  The first operation involved in a Carnot cycle is  [AFMC 1998]
  A)
             Isothermal expansion       done clear
  B)
             Adiabatic expansion done clear
  C)
             Isothermal compression  done clear
  D)
             Adiabatic compression  done clear
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• question_answer27)
  For which combination of working temperatures the efficiency of Carnot?s engine is highest       [KCET 2000]
  A)
             80 K, 60 K                                done clear
  B)
             100 K, 80 K done clear
  C)
             60 K, 40 K                                done clear
  D)
             40 K, 20 K  done clear
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• question_answer28)
  The efficiency of Carnot engine when source temperature is T1 and sink temperature is T2 will be             [DCE 2000]
  A)
             \[\frac{{{T}_{1}}-{{T}_{2}}}{{{T}_{1}}}\]                         done clear
  B)
              \[\frac{{{T}_{2}}-{{T}_{1}}}{{{T}_{2}}}\] done clear
  C)
             \[\frac{{{T}_{1}}-{{T}_{2}}}{{{T}_{2}}}\]                         done clear
  D)
             \[\frac{{{T}_{1}}}{{{T}_{2}}}\] done clear
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• question_answer29)
  An ideal heat engine working between temperature T1­ and T2 has an efficiency h, the new efficiency if both the source and sink temperature are doubled, will be        [DPMT 2000]
  A)
             \[\frac{\eta }{2}\]               done clear
  B)
              \[\eta \] done clear
  C)
             \[2\eta \]                                done clear
  D)
             \[3\eta \] done clear
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• question_answer30)
  An ideal refrigerator has a freezer at a temperature of \[-13{}^\circ C.\] The coefficient of performance of the engine is 5. The temperature of the air (to which heat is rejected) will be [BHU 2000; CPMT 2002]
  A)
             325°C                                        done clear
  B)
              325K done clear
  C)
             39°C                                          done clear
  D)
              320°C done clear
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• question_answer31)
  In a mechanical refrigerator, the low temperature coils are at a temperature of ? 23°C and the compressed gas in the condenser has a temperature of 27°C. The theoretical coefficient of performance is                                        [UPSEAT 2001]
  A)
             5     done clear
  B)
              8 done clear
  C)
             6     done clear
  D)
              6.5 done clear
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• question_answer32)
  An engine is supposed to operate between two reservoirs at temperature 727°C and 227°C. The maximum possible efficiency of such an engine is          [UPSEAT 2005]
  A)
             1/2                                            done clear
  B)
              1/4 done clear
  C)
             3/4 done clear
  D)
              1 done clear
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• question_answer33)
  An ideal gas heat engine operates in Carnot cycle between 227°C and 127°C. It absorbs \[6\times {{10}^{4}}\] cals of heat at higher temperature. Amount of heat converted to work is  [CBSE PMT 2005]
  A)
             \[2.4\times {{10}^{4}}\]cal      done clear
  B)
             \[6\times {{10}^{4}}\] cal done clear
  C)
             \[1.2\times {{10}^{4}}\] cal     done clear
  D)
             \[4.8\times {{10}^{4}}\] cal done clear
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• question_answer34)
  Which of the following processes is reversible  [CBSE PMT 2005]
  A)
             Transfer of heat by radiation                                             done clear
  B)
             Electrical heating of a nichrome wire done clear
  C)
             Transfer of heat by conduction done clear
  D)
             Isothermal compression done clear
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