2022Flame Institute

30. In a thermodynamic system working substance is ideal gas, its internal energy is in the form of

(a) Kinetic energy only (b) Kinetic and potential energy (c) Potential energy (d) None of these Ans. a (4)

26. Which of the following is not a thermodynamics co-ordinate

(a) P (b) T (c) V (d) R Ans. d (9)

16. Which of the following is not thermodynamical function

(a) Enthalpy (b) Work done (c) Gibb’s energy (d) Internal energy Ans. b (12)

15. 110 J of heat is added to a gaseous system, whose internal energy change is 40 J, then the amount of external work done is

(a) 150 J (b) 70 J (c) 110 J (d) 40 J Ans. b (5)

14. A container of volume

1m3 is divided into two equal compartments by a partition. One of these compartments contains an ideal gas at 300 K. The other compartment is vacuum. The whole system is thermally isolated from its surroundings. The partition is removed and …

13. A system performs work

Δw when an amount of heat is ΔQ added to the system, the corresponding change in the internal energy is ΔU . A unique function of the initial and final states (irrespective of the mode of change) is (a) …

12. Find the change in internal energy of the system when a system absorbs 2 kilocalorie of heat and at the same time does 500 joule of work

(a) 7900 J (b) 8200 J (c) 5600 J (d) 6400 J Ans. a (5)

37. One mole of an ideal monoatomic gas is heated at a constant pressure

of one atmosphere from 00c to 1000c . Then the change in the internal energy is (a) 6.56 joules (b) 8.32 x 102 joules (c) 12.48 x 102 joules (d) 20.80 joules Ans. c (15)

58. The kinetic energy of one gm-mole of a gas at normal temperature and pressure is (R = 8.31 J/Mole-K)

(a) 0.56×104 J (b) 1.3×102 J (c) 2.7×102 J (d) 3.4×103 J Answer-d (6)

57. The temperature at which the average translational kinetic energy of a molecule is equal to the energy gained by an electron in accelerating from rest through a potential difference of 1 volt is

(a) 4.6×103 K (b) 11.6×103 K (c) 23.2×103 K (d) 7.7×103 K Answer-d (4)

36. First law of thermodynamics is a special case of

(a) Newton’s law (b) Law of conservation of energy (c) Charle’s law (d) Law of heat exchange Ans. b (5)

56. Mean kinetic energy per degree of freedom of gas molecules is

(a) (3/2)kT (b) kT (c) (1/2)kT (d) (3/2)RT Answer-c …

55. The molecules of an ideal gas at a certain temperature have

(a) Only potential energy (b) Only kinetic energy (c) Potential and kinetic energy both (d) None of the above Answer-b (10)

35. Out of the following which quantity does not depend on path

(a) Temperature (b) Energy (c) Work (d) None of these Ans. a (9)

54. Two ideal gases at absolute temperature

T1 and T2 are mixed. There is no loss of energy. The masses of the molecules are m1 and m2 and the number of molecules in the gases are n1 and n2 The temperature of mixture will be (a) (T1 …

53. The total momentum of the molecules of 1 gm mol of a gas in a container at rest of 300 K is

(a) 2×√3R×300 gm×cm/sec (b) 2×3×R×300 gm×cm/sec (c) 1×√3R×300 gm×cm/sec (d) Zero Answer-d (10)

33. In a thermodynamic process, pressure of a fixed mass of a gas is changed in such a manner that the gas molecules gives out 20 J of heat and 10 J of work is done on the gas. If the initial internal energy of the gas was 40 J, then the final internal energy will be

(a) 30 J (b) 20 J (c) 60 J (d) 40 J Ans. c (5)

52. In the absence of intermolecular force of attraction, the observed pressure P will be

(a) P (b) < P (c) > P (d) Zero Answer-c (4)

51. Vapour is injected at a uniform rate in a closed vessel which was initially evacuated. The pressure in the vessel

(a) Increase continuously (b) Decreases continuously (c) First increases and then decreases (d) First increase and then becomes constant Answer-c (4)

50. The capacity of a vessel is 3 litres. It contains 6 gm oxygen, 8 gm nitrogen and 5 gm

CO2 mixture at 27°C. If R = 8.31 J/mole kelvin, then the pressure in the vessel in N/m2 will be (approx.) (a) 5×105 (b) 5×104 (c) 106 …

31. Which of the following statements is correct for any thermodynamic system

(a) The internal energy changes in all processes (b) Internal energy and entropy are state functions (c) The change in entropy can never be zero (d) The work done in an adiabatic process is always zero (19)

49. The mean kinetic energy of a gas at 300 K is 100 J. The mean energy of the gas at 450 K is equal to

(a) 100 J (b) 3000 J (c) 450 J (d) 150 J Answer-d (17)

48. On colliding in a closed container the gas molecules

(a) Transfer momentum to the walls (b) Momentum becomes zero (c) Move in opposite directions (d) Perform Brownian motion Answer-a (24)

29. Which of the following parameters does not characterize the thermodynamic state of matter

(a) Volume (b) Temperature (c) Pressure (d) Work Ans. d (4)

28. The specific heat of hydrogen gas at constant pressure

is Cp=3.4 x 103 cal/kg 0c and at constant volume is Cv= 2.4 x103 cal/kg 0c. If one kilogram hydrogen gas is heated from 10 0c to 200c at constant pressure, the external work done on the gas to maintain …