FSc ICS Notes Entry Test Exam Solution MCAT ECAT Physics First Year Chapter 11 Heat and Thermodynamics

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1. The centigrade and Fahrenheit scales will have the same reading when the temperature is:

• 70
• -80
• -40
• 120

2. The Fahrenheit and kelvin scale will have the same reading when the temperature is:

• 370
• 574.25
• 414.5
• 388

3. Fahrenheit scale was originally used in:

• Meteorology
• Clinical thermometer
• Clinical thermometer and meteorology
• None of these

4. A gas which strictly obeys the gas laws under all conditions of temperature and pressure is called:

• Real gas
• Ideal gas
• Inert gas
• None of these

5. The motion of molecules in gases is:

• Orderly
• Random
• Circular
• All of these

6. At constant temperature, if the density of the gas is increased, its pressure will:

• Decrease
• Increase
• Remains unchanged
• None of these

7. If a molecule will momentum mv strikes a wall and rebound then the change in momentum will be:

• -2mv
• Zero
• 2mv
• mv

8. Given that P=10(4) N/m2, area of the piston = 0.1 m(2) and distance moved by the piston = 10(-1) cm, then the work done by the gas is:

• 1J
• 10(5)J
• 10(4)J
• 10J

9. If Cv denotes molar specific heat at constant volume and ?T is the change in the temperature, then Cv∆T gives:

• Volume
• Pressure
• Energy
• Entropy

10. If temperature of the sink is decreased, efficiency of a Carnot engine:

• Remains constant
• Decreases
• Increases
• None of these

11. One degree of thermodynamic scale is equal to ________ of the temperature triple point of water.

• 1/273 th
• 1/100 th
• 1/273.16 th
• 1/32 th

12. The unknown temperature T on thermodynamic scale in kelvin is given by the formula:

• T = 273.16Q/Q3
• T = 32Q/Q3
• T = 100Q/Q3
• T = 273Q/Q3

13. A certain engine converts 20% of available heat into work. Then its efficiency will be:

• 20%
• 80%
• 50%
• None of these

14. Number of spark plugs needed in diesel engine is:

• Four
• Five
• Six
• None of these

15. Most motorbikes have ________ cylinder/s engine but cars usually have cylinders on the same crankshaft.

• Four, six
• One, four
• Two, five
• None of these

16. A constant volume gas thermometer works on:

• Archimedes principle
• Pascal's law
• Boyle's law
• Charles law

17. The ratio of coefficients of cubical expansion and linear expansion is:

• 1:1
• 3:1
• 2:1
• None of these

18. When a copper ball is heated, the largest percentage in crease will occur in its:

• Diameter
• Area
• Volume
• Density

19. Sea animals are safe in winter in cold countries because of:

• Their body conditions
• High specific heat of water
• Low conductivity of water
• Anomalous expansion of water

20. The volume expansion coefficient is:

• Equal to temperature
• Proportional to square root of temperature
• Inversely proportional to square root of temperature
• Inversely proportional to temperature

21. Heat is transferred most rapidly by the process of:

• Conduction
• Convection
• Radiation
• Combustion

22. When water is heated from 0 degree to 10 degree Celsius, its volume:

• Increases
• Decreases
• Does not change
• Data is insufficient

23. First law of thermodynamic concerns conservation of:

• Heat
• Work
• Momentum
• Energy

24. When 110J of heat is added to a gaseous system, internal energy increases by 40J; the amount of work done is:

• 150J
• 70J
• 110J
• 40J

25. Molar specific heat at constant volume Cv for a mono-atomic gas is:

• 3/2 R
• 5/2 R
• 6/2 R
• 4/2 R

26. A sink, that is a system where heat is rejected, is essential for the conservation of heat into work. From which law the above inference follows?

• Zeroth
• First
• Second
• Third

27. The first operation involved in a Carnot cycle is:

• Isothermal expansion
• Adiabatic expansion
• Isothermal compression
• Adiabatic compression

28. An ideal heat engine exhausting heat at 77 degree Celsius is to have a 30% efficiency. It must take heat at:

• 127 degree Celsius
• 227 degree Celsius
• 327 degree Celsius
• 673 degree Celsius

29. The work done in an adiabatic change in a particular gas depends upon only:

• Change in volume
• Change in pressure
• Change in temperature
• None of these

30. The gas law Constant = PV/T is true for:

• Isothermal changes only
• Adiabatic changes only
• Both isothermal and adiabatic changes
• Neither for isothermal nor for adiabatic changes

31. The physical quantity which described the level of thermal energy in a body is:

• Temperature
• Heat energy
• Pressure
• Volume

32. The pressure exerted by the gas is directly proportional to:

• Velocity of the molecule
• Density of the gas
• Square of the density
• Square root of the density

33. For an ideal gas system, the internal energy is directly proportional to:

• Pressure
• Volume
• Density
• Temperature

34. The change in internal energy of the system is positive, when the temperature of the system:

• Increases
• Decreases
• Remains constant
• None of the above

35. Water boils at 100 degree Celsius, the corresponding temperature at Fahrenheit scale is:

• 180 Fahrenheit
• 200 Fahrenheit
• 212 Fahrenheit
• 273 Fahrenheit

36. A Celsius degree is larger than a Fahrenheit degree by:

• 5/9
• 9/5
• 9/10
• 9/8

37. Absolute zero is considered as that temperature at which:

• All liquids become gases
• All gases become liquids
• Water freezes
• All gases partially liquefied

38. At constant volume, the graph between P and T is:

• Hyperbola
• Parabola
• Straight line
• Ellipse

39. At constant temperature, if the pressure of the given mass of the gas is doubled, then the density of the gas becomes:

• Double
• 1/4 of the original value
• 1/2 of the original value
• Remains constant

40. An inflated tire suddenly bursts. As a result of this, the temperature of air:

• Increases
• Decreases
• May increase or decrease
• Remains constant

41. When the gas expands isothermally, the work is:

• Done on the gas
• Done by the gas
• Zero
• Negative

42. The SI unit of molar specific heat is:

• Jmol/K
• J/molK
• JK/mol
• J/mol

43. The coefficient of linear expansion of platinum is 9*10(-6) per Coulomb. Its coefficient of volume expansion is:

• 3*10(-6) per Coulomb
• 9*10(-6) per Coulomb
• 18*10(-6) per Coulomb
• 27*10(-6) per Coulomb

44. The SI unit of entropy is:

• J/K
• J/s
• Js/K
• J/K(2)

45. The natural process tends to proceed towards a state of greater:

• Order
• Disorder
• Both order and disorder
• Neither order nor disorder

46. Which of the following is not the function of state?

• Internal energy
• Entropy
• Enthalpy
• Mass

47. Entropy of universe during any natural process:

• Increases
• Increases or remains constant
• Decreases
• Decreases or remains constant

48. When a sphere is heated, then the greatest increase is in its:

• Radius
• Circumference
• Surface area
• Volume

49. Net change in entropy of a system in a Carnot's cycle is:

• Positive
• Negative
• Maximum
• Zero

50. Area under the p-v graph of Carnot engine represents the:

• Heat absorbed
• Heat rejected
• Total work done
• All of the above

51. Temperature of gas is a measure of:

• the average translational kinetic energy of the gas molecule
• the average potential energy of the gas molecules
• the average distance of the gas molecules
• the size of the gas molecules

52. A thermometric liquid which can be used to measure temperature between -40 degree Celsius to 40 degree Celsius is:

• Water
• Alcohol
• Mercury
• Phenol

53. The temperature at which the reading of a Fahrenheit thermometer will be double that of Centigrade thermometer is:

• 160 degree Celsius
• 180 degree Celsius
• 32 degree Celsius
• 100 degree Celsius

54. For measuring temperature near absolute zero, the thermometer used is:

• Thermoelectric thermometer
• Radiation thermometer
• Magnetic thermometer
• Resistance thermometer

55. The absolute zero is the temperature at which:

• Water freezes
• All substances exist in solid state
• Molecular motion ceases
• None of the above

56. Absolute zero (0K) is that temperature at which:

• Matter ceases to exist
• Ice melts and water freezes
• Molecular motion ceases
• None of the above

57. The temperature on Celsius scale is 25 degree Celsius. What is the corresponding temperature on the Fahrenheit scale?

• 40 F
• 77 F
• 50 F
• 45 F

58. The root mean square speed of the molecules of different ideal gases, maintained at the same temperature are:

• Same
• Different
• Zero
• Infinity

59. 'P' is pressure and 'd' is the density of the gas at constant temperature, then:

• P ∝ 1/d
• P ∝ 1/d(2)
• P ∝ d
• P ∝ d(2)

60. The number of molecules per cc of a gas at S.T.P. is:

• 2.68*10(17)
• 2.68*10(19)
• 22400*6*10(23)
• 6*10(23)

61. In winter, the temperature of the inside wall of a room as compared to the temperature of air in the room is:

• Lower
• Higher
• Same
• May be lower or higher depending upon atmospheric pressure

62. Pressure of a gas can be written as:

• 1/3 ρV
• 1/3 V(2)
• 1/3 ρV(2)
• 1/3 ρ(2)V

63. One Kelvin is defined as:

• 1/100 of boiling point of water
• 1/273.16 of melting of ice
• 1/273.16 of boiling point of water
• 1/273.16 of temperature of triple point of water

64. The value of Boltzmann's constant is:

• 1.38*10(-23)J/K
• 1.38*10(23)J/K
• 1.38*10(-23)J/mole-K
• 1.38*10(-23)J/K mole-K

65. For a gas obeying Boyle's law if the pressure is doubled, the volume becomes:

• Double
• One half
• Three fold
• Remains the same

66. If coefficient of linear expansion of a solid is a, its coefficient of cubical expansion will be approximately:

• 2a
• 3a
• 2.5a
• 4a

67. The SI units of specific heat are:

• K cal / kg K
• Cal / gram C
• K cal / kg C
• J / kg K

68. In an adiabatic process:

• Q = ∆U + W
• Q = ∆U
• Q = W
• Q = 0

69. A system does 600 J of work and at the same time its internal energy increased by 320J. How much heat has  bee supplied?

• 280J
• 920J
• 600J
• 20J

70. No entropy change takes place in:

• Isothermal process
• Adiabatic process
• Isobaric process
• Isochoric process