Practice Test 4

Choose the best answer

  1. Temperature of a subtance is
    1. a measure of the amount of heat an object has.
    2. a measure of the total kinetic energy of the
      particles comprising the substance.
    3. a measure of the average potential energy of the
      particles comprising the substance.
    4. a measure of the average kinetic energy of the
      particles comprising the substance.
    5. a measure of the total potential energy of the
      particles comprising the substance
    Answer: D

  2. 90 �F is equal to
    1. 26.634 �C
    2. 32.222 �C
    3. 56.89 �C
    4. 45.192 �C
    5. 10.908 �C
    Answer: B

  3. A thermometer is based on the change of volume
    with change in temperature of a fluid in a tube.
    The fluid rises to a level of 0.01 m when the temperature is
    5.5 � C and to a level of 0.13 m when the temperature is
    19 � C. Obtain the calibrating equation; that is a formula
    for the temperature ( T ) in terms of the fluid level ( L ).
    1. T = 96.3 * L + 2.818
    2. T = 96.3 * L + 4.375
    3. T = 112.5 * L + 4.961
    4. T = 112.5 * L + 4.375
    5. T = 149.962 * L + 4.961
    Answer: D

  4. By how much should the temperature of an aluminum
    rod of length 2 m change if its length is to change by 8.5e-3 m.
    (Coeeficient of linear expansion for aluminum
    is 2.4e-5 ⁄ �C.)
    1. 327.469 �C
    2. 177.083 �C
    3. 293.193 �C
    4. 251.808 �C
    5. 273.118 �C
    Answer: B

  5. A circular plate made of steel has a radius of 0.8 m
    at a temperature of 20 �C. Calculate its radius at a temperature
    of 200 �C. (Coefficient of linear expansion of
    steel is 1.1e-5 ⁄ �C)
    1. 0.8063 m
    2. 0.8047 m
    3. 0.8016 m
    4. 0.8002 m
    5. 0.8032 m
    Answer: C

  6. Which of the following is a correct statement.
    1. The combined gas law states that the volume of a
      gas is directly proportional to its pressure and
      inversely proportional to its temperature.
    2. Boyle's law states that if the temperature of a
      gas is kept constant, then the volume and
      the pressure of the gas are directly proportional.
    3. Charles' law states that if pressure is kept
      constant, then the volume and the
      temperature of the gas are inversely proportional
    4. Charles' law states that if the temperature of a
      gas is kept constant, then the volume and
      the pressure of the gas are inversely proportional.
    5. Boyle's law states that if the temperature of a
      gas is kept constant, then the volume and
      the pressure of the gas are inversely proportional.
    Answer: E

  7. A gas has a temperature of 80 �C when its volume is
    90 L and its pressure is 20 kPa. Calculate its temperature when its
    volume is 95 L and its pressure is 45 kPa.
    1. 244.923 �C
    2. 565.375 �C
    3. 508.222 �C
    4. 653.614 �C
    5. 84.29 �C
    Answer: B

  8. Calculate the temperature of 40 g of di-atomic chlorine ( Cl2 )
    gas that occupies a volume 100 L at a pressure of 70 kPa.
    (atomic mass of chlorine is 35 u ).
    1. 1202.904 �C
    2. 1548.27 �C
    3. 2086.001 �C
    4. 2252.706 �C
    5. 1040.931 �C
    Answer: A

  9. How many molecules are there in a sample of gas
    that occupies a volume 10 L at STP.
    1. 1.031e23
    2. 4.334e23
    3. 3.523e23
    4. 2.689e23
    5. 2.409e23
    Answer: D

  10. A 10 g sample of di-atomic Chlorine ( Cl2 ) gas is at a
    temperature of 30 �C. Calculate the total energy
    (translational kinetic energy) of the sample. (atomic mass
    of chlorine is 35 u. )
    1. 538.907 J
    2. 929.447 J
    3. 253.255 J
    4. 119.361 J
    5. 484.599 J
    Answer: A

  11. One calorie of heat energy is equal to
    1. 10 J
    2. 100 J
    3. 4180 J
    4. 418 J
    5. 4.18 J
    Answer: E

  12. When a sample of lead (specific heat 130 J ⁄ kg ⁄ �C) is
    supplied with a 24000 J of heat energy, its temperature increased
    from 28 �C to 82 �C. Calculate the mass of
    the sample.
    1. 3.419 kg
    2. 2.36 kg
    3. 5.183 kg
    4. 4.101 kg
    5. 6.475 kg
    Answer: A

  13. 0.75 kg of a certain substance at a temperature of
    125 �C is mixed with 10 kg of water (specific heat capacity
    4180 J ⁄ kg ⁄ �C) at a temperature of 24 �C.
    The equilibrum temperature of the mixture is found to be
    48 �C. Calculate specific heat capacity of the substance.
    1. 17371.429 J ⁄ kg ⁄ �C
    2. 19331.447 J ⁄ kg ⁄ �C
    3. 28367.91 J ⁄ kg ⁄ �C
    4. 32950.904 J ⁄ kg ⁄ �C
    5. 25686.107 J ⁄ kg ⁄ �C
    Answer: A

  14. Calculate the amount of water (Latent heat of vaporization
    2.26e6 J ⁄ kg) that can be vaporized by 7e6 J of heat energy.
    1. 4.708 kg
    2. 3.097 kg
    3. 0.861 kg
    4. 4.242 kg
    5. 5.567 kg
    Answer: B

  15. Calculate the amount of heat energy required to
    change 0.457 kg of water at a temperature of 20 �C to steam at a
    temperature of 150 �C. (specific heat capacities
    of ice, water and steam are 2090, 4180, 2010 J ⁄ kg ⁄ �C
    respectively. Latent heat of fusion and vaporization of water are
    3.34e5, 2.26e6 J ⁄ kg respectively.)
    1. 209910.064 J
    2. 1088055.193 J
    3. 865187.468 J
    4. 1231569.3 J
    5. 2029388.096 J
    Answer: D

  16. Which of the following is not a correct statement?
    1. The rate of absorption of radiation by an object
      is proportional to the surface area of the object.
    2. The net rate of emission of radiation is equal
      to the difference between the emission and
      the absorption rate.
    3. The rate of absorption of radiation by an object
      is proportional to the fourth power of its
      temperature.
    4. The rate of emission of radiation by an object
      is proportional to the fourth power of its
      temperature.
    5. The rate of emission of radiation by an object
      is proportional to the surface area of the object
    Answer: C

  17. A rod made of copper (thermal conductivity 397 J ⁄ s ⁄ m ⁄ �C)
    has a length of 4 m and a cross-sectional radius of 0.0175 m.
    Its left end and right end are at temperatures of 24 �C and 125 �C
    respectively. Calculate the amount of energy transferred
    from the left end to the right end in 42 minutes.
    1. 42245.883 J
    2. 7060.5 J
    3. 15893.463 J
    4. 24304.036 J
    5. 12574.558 J
    Answer: D

  18. An spherical object of radius 0.6 m and emissivity 0.2 is at a
    temperature of 60 �C. Its enviornment is at a temperature of 13 �C.
    Calculate the rate at which the object is emitting radiation
    to its enviornment.
    1. 634.153 W
    2. 836.136 W
    3. 122.177 W
    4. 1020.808 W
    5. 723.994 W
    Answer: A

  19. An spherical object of radius 0.4 m and emissivity 0.9 is at a
    temperature of 90 �C. Its enviornment is at a temperature of 16 �C.
    Calculate the rate at which the object is absorbing radiation
    from the enviornment.
    1. 94.778 W
    2. 719.513 W
    3. 465.126 W
    4. 1275.479 W
    5. 1062.765 W
    Answer: B

  20. Two systems are said to be in thermodynamic
    equilibrium if
    1. if they have the same kinetic energy.
    2. they have the same energy.
    3. if they are at rest
    4. they have the same temperature.
    5. they have the same pressure.
    Answer: D

  21. The internal energy of a system of gas decreased
    by 100 J while being supplied with 250 J of heat energy.
    Calculate the work done by (on) the system.
    1. 0 J
    2. -350 J
    3. -150 J
    4. 150 J
    5. 350 J
    Answer: E

  22. In a cyclic process, the volume of a system of gas
    decreased by 10 L under a pressure of
    200 kPa. Which of the following is a
    true statement.
    1. 2000 J of work was done by the system on the
      enviornment.
    2. The change in internal energy or the heat supplied
      (lost) can not be determined based on the given information
    3. The internal energy of the system increased by 2000 J.
    4. The system gained 2000 J of heat energy.
    5. The change in internal energy of the system is zero.
    Answer: E

  23. The following is a PV dagram for a certain system of gas.



    Calculate the work done in taking the system from the point D( 2 L, 4 kPa)
    to the point B( 6 L, 2 kPa) along path DCB.
    1. -16 J
    2. -8 J
    3. 24 J
    4. 16 J
    5. 8 J
    Answer: D

  24. The following is a PV dagram for a certain system of gas.



    Calculate the work done by (on) the system for the cyclic
    process ADCBA.
    1. 16 J
    2. -8 J
    3. 8 J
    4. -16 J
    5. 0 J
    Answer: C

  25. Which of the following statements is not a correct
    statement.
    1. The efficiency of a heat engine can never be a 100%.
    2. An isolated system can only proceed from order
      to disorder.
    3. The entropy of an isolated system can only decrease.
    4. The universe tends to go from order to disorder.
    5. The entropy of the gas state is greater than the
      entropy of the liquid state.
    Answer: C

  26. A heat engine absorbs 1844 J of energy
    from a hot reservior at a temperature of 340 �C
    and gives off 833 J of energy to a cold
    reservior at a temperature of 32 �C in a cyclic process.
    Calculate the efficiency of the engine.
    1. 40.69%
    2. 11.862%
    3. 85.113%
    4. 21.762%
    5. 54.826%
    Answer: E

  27. Calculate the maximum possible efficiency for a
    heat engine that operates between a hot reservior
    at a temperature of 310 �C and a cold reservior
    at a temperature of 20 �C.
    1. 93.305%
    2. 49.743%
    3. 86.654%
    4. 37.47%
    5. 77.169%
    Answer: B