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Set 11 of 17 · Questions 301-330 of 484

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JEE Main Physics · Thermodynamics · Set 11 (Q301-330)

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  1. 301.
    In a thermodynamic process if ' and ' ' are the work done and change in the internal energy of a system respectively, then
    1. (1) in adiabatic process
    2. (2) in isothermal process
    3. (3) in isothermal process
    4. (4) in adiabatic process
  2. 302.
    “Heat cannot by itself flow from a body at lower temperature to a body at higher temperature” is a statement or consequence of
    1. (1)Second law of thermodynamics
    2. (2)Conservation of momentum
    3. (3)Conservation of mass
    4. (4)First law of thermodynamics
  3. 303.
    Two moles of a gas is expanded to double its volume by two different processes. One is isobaric and the other is isothermal. If and are the works done, respectively then
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  4. 304.
    For an adiabatic expansion of an ideal gas, the fractional change in its pressure is equal to (where is the ratio of specific heats):
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  5. 305.
    An ideal heat engine has an efficiency . The coefficient of performance of the engine when driven backward will be
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  6. 306.
    The amount of heat energy required to raise the temperature of 1 ofHelium at NTP, from to is
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  7. 307.
    The change in density of mercury, when it is heated from to is (The coefficient of volume expansion of mercury is ).
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  8. 308.
    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
    1. (1)It is impossible
    2. (2)It is possible but less probable
    3. (3)It is quite probable
    4. (4)Data are incomplete
  9. 309.
    The entropy of any system is given by

    where and are the constants. and R are no. of moles, mechanical equivalent of heat, Boltzmann constant and gas constant respectively.

    Choose the incorrect option from the following:
    1. (1) and J have the same dimensions.
    2. (2)and have the same dimensions.
    3. (3)S and have different dimensions.
    4. (4) and k have the same dimensions.
  10. 310.
    A meter scale made of steel, reads accurately at . Suppose in an experiment an accuracy of in is reqnired, the range of temperature in which the experiment can be performed with this meter scale is (Coefficient of linear expansion of steel is )
    1. (1) to
    2. (2) to
    3. (3) to
    4. (4) to
  11. 311.
    An ideal gas heat engine, exhausting heat at 77° C has a 30% efficiency. It must take heat at
    1. (1)127° C
    2. (2)227 ° C
    3. (3)327° C
    4. (4)673°C
  12. 312.
    Statement (I): A device in which heat measurement can be made is called calorimeter.
    Statement (II): Skating is possible on snow due to the formation of water below the skates. Water is formed due to the increase of temperature and ice melts.
    Statement (III): Two bodies at different temperature are mixed in a calorimeter. Total internal energy of the two bodies remains conserved.
    Which of the following is correct?
    1. (1)Statements I, II and III are true
    2. (2)Statement is true, but statements II and III are false
    3. (3)Both statements I and II are true, but statement III is false
    4. (4)Both statements I, III are true, but statement II is false
  13. 313.
    Steam at is added to water to increase its temperature from to . The total mass of the water at is (specific heat capacity of water and latent heat of steam )
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  14. 314.
    If the co-efficient of performance of a refrigerator is 5 and operates at the room temperature 27°C, the temperature inside the refrigerator is
    1. (1)240 K
    2. (2)250 K
    3. (3)230 K
    4. (4)260 K
  15. 315.
    A carnot engine takes 900 kcal of heat from a reservoir at 723°C and exhausts it to a sink at 30°C. The work done by the engine is
    1. (1)2.73 × Cal
    2. (2)3.73 × Cal
    3. (3)6.27 × Cal
    4. (4)3.73 × Cal
  16. 316.
    A Carnot engine working between 300 K and 600 K has a work output of 800 J per cycle. The amount of heat energy supplied to the engine from the source per cycle is -
    1. (1)1200 J
    2. (2)2400 J
    3. (3)1600 J
    4. (4)3200 J
  17. 317.
    A balloon filled with helium ( and atm.) bursts. Immediately afterwards the expansion of helium can be considered as
    1. (1)Irreversible adiabatic
    2. (2)Reversible adiabatic
    3. (3)Irreversible isothermal
    4. (4)Reversible isothermal
  18. 318.
    For a diatomic gas, if for rigid molecules and for another diatomic
    molecules, but also having vibrational modes. Then, which one of the following options is correct? (Cp and Cv are specific heats of the gas at constant pressure and volume)
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  19. 319.
    A Carnot engine take 5000 kcal of heat from a reservoir at 727°C and gives heat to a sink at 127°C. The work done by the engine is:
    1. (1)J
    2. (2)Zero
    3. (3)12.J
    4. (4)8.J
  20. 320.
    Two heat engines A and B have their sources at 1000 K and 1100 K and their sinks are at 500 K and 400 K respectively. What is true about their efficiencies?
    1. (1)ηA = ηB
    2. (2)ηA>ηB
    3. (3)ηA<ηB
    4. (4)Cannot predict.
  21. 321.
    In a Carnot's engine if the temperatures of the source and the sink are decreased by each then the efficiency of the engine
    1. (1)increases
    2. (2)decreases
    3. (3)remains constant
    4. (4)becomes one
  22. 322.
    The specific heat of helium at constant volume is 12.6 . The specific heat of helium at constant pressure in is approximately (assume, the universal gas constant, )
    1. (1)12.6
    2. (2)16.8
    3. (3)18.9
    4. (4)20.9
  23. 323.
    A hammer of mass strikes a steel block of mass with a velocity . If of the energy is utilized to heat the steel block, the rise in temperature of the block is (specific heat capacity of steel )
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  24. 324.
    The phenomena of lowering freezing point of water by the application of pressure is known as
    1. (1)Sublimation
    2. (2)Regelation
    3. (3)Precipitation
    4. (4)Crystallization
  25. 325.
    Three very large plates of same area are kept parallel and close to each other. They are considered as ideal black surfaces and have very high thermal conductivity. First and third plates are maintained at absolute temperatures and respectively. Temperature of the middle plate in steady state is
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  26. 326.
    When the door of a refrigerator is kept open then the room temperature starts
    1. (1)Cool down
    2. (2)Hot up
    3. (3)First cool down then hot up
    4. (4)Neither cool down nor hot up
  27. 327.
    A Carnot engine operating between temperatures and , absorbs of heat from the source. The mechanical work done per cycle is
    1. (1)
    2. (2)
    3. (3)
    4. (4)
  28. 328.
    An electric appliance supplies 6000J/min heat to the system. If the system delivers a power of 90W. How long it would take to increase the internal energy by 2.J?
    1. (1)2.s
    2. (2)4.1 s
    3. (3)2.4 s
    4. (4)2.s
  29. 329.
    A diatomic gas does 100 J of work when it is expanded isobarically. Then the heat given to the gas J.
  30. 330.
    The temperature of 1 mole of an ideal monoatomic gas is increased by at constant pressure. The total heat added and change in internal energy are and , respectively. If then the value of is .