# Kinetic Theory of Gases – Question Paper 03

 1 5 gm of air is heated from 273°K to 275°K. the change in internal energy of air will be (CV = 172 cal/kg °K and 4.2 J/cal) (MHT-CET-2001) (a) 7.22 J (b) 5.22 J (c) 8.16 J (d) 3.5 J Answer: (a) 2 Moon has no atmosphere because (a) It is far away form the surface of the earth (b) Its surface temperature is 10°C (c) The r.m.s. velocity of all the gas molecules is more then the escape velocity of the moon’s surface (d) The escape velocity of the moon’s surface is more than the r.m.s velocity of all molecules Answer: (c) 3 An ideal gas exert a pressure P. the mean kinetic energy per unit volume is E. which of the following relations is correct – (MP-PMT-94, CBSE-93, AFMC-93) (a) P = E (b) (c) (d) Answer: (c) 4 According to kinetic theory of gasses at absolute zero temperature (CBSE-90) (a) Water freezes (b) Liquid helium freezes (c) Molecules motion stops (d) Liquid hydrogen freezes Answer: (c) 5 If 1 kg of water at its normal boiling point forms 1.671 m3 of steam, the external latent heat of vaporization of water is about (J = 4200 J/kcal) (MHT-CET 2005) (a) 400 kcal/kg (b) 40 kcal/kg (c) 4 kcal/kg (d) 40 cal/kg Answer: (b) 6 One mole of an ideal gas requires 207 J heat to raise the temperature by 10 K, when heated at constant pressure. If the same gas is heated at constant volume to raise the temperature by 10K, then heat required is (MHT-CET-2000) (a) 96.6 J (b) 124 J (c) 198.8 J (d) 215.4 J Answer: (b) 7 If P is the exerted by a gas and E is the K.E. per unit volume, then (a) (b) (c) (d) Answer: (b) 8 A gas at a pressure P0 is contained in a vessel. If the masses of all the molecules are halved and their velocities doubled, the resulting pressure P would be equal to (CPMT-91) (a) 4 P0 (b) 2 P0 (c) P0 (d) Answer: (b) 9 For an ideal gas, is (a) > 1 (b) < 1 (c) = 1 (d) ≥ 1 Answer: (b) 10 A gas in a container A is in thermal equilibrium with another gas of the same mass in container B. if we denote the corresponding pressures and volumes by the suffices A and B, then which of the following statement is most likely to be true (AIIMS-82) (a) PA = PB, VA ¹ VB (b) PA ≠ PB, VA = VB (c) (d) PA VA = PB VB Answer: (c) 11 Boyl’s law is applicable in, (AFMC 94) (a) Isochoric process (b) Isothermal process (c) Isobaric process (d) Isotonic process Answer: (b) 12 Real gases show mark able deviation from that of ideal gas behavior at (MHT-CET 2003) (a) High temperature and low pressure (b) Low temperature and high pressure (c) High temperature and high pressure (d) Low temperature and low pressure Answer: (b) 13 If the pressure of an ideal gas is decreased by 10% isothermally, then its volume will (a) Increase by 10% (b) Increase by 11.1% (c) Decrease by 10% (d) Decrease by 9% Answer: (b) 14 One any planet, the presence of atmosphere implies [νrms = root mean square velocity of molecules and νe = escape velocity]  (RAJ-PMT 96) (a) νrms << νe (b) νrms > νe (c) νrms = νe (d) νrms = 0 Answer: (a) 15 The equation of state corresponding to 8 g of O2 is, (CBSE-94) (a) (b) (c) PV = RT (d) PV = 8RT Answer: (b) 16 Which of the following properties of gas molecule the one that is same for all ideal gases at a particular temperature is (MHT-CET-2001) (a) Mass (b) Velocity (c) Momentum (d) Kinetic energy Answer: (a) 17 Which of the following is the unit of specific (MHT-CET 2004) (a) J kg/°c (b) J/kg°c (c) kg °c/J (d) J kg/°c2 Answer: (b) 18 If E is the kinetic energy per mole of a gas, and T is the absolute temperature, then the universal gas constant is given by (a) (b) (c) (d) Answer: (b) 19 N molecules, each of mass m, of gas A and 2 N molecules, each of mass 2 m, of gas B are contained in the same vessel which maintained at a temperature T. the mean square of he velocity of molecules of B type is denoted by ν2 and the mean square of the X component of the velocity of A type is denoted by ω2, then is (NCERT-84) (a) 2 (b) 1 (c) (d) Answer: (d) 20 Consider a gas with density ρ and C as the root mean square velocity of its molecules contained in a volume. If the system moves as a whole with velocity ν, then the pressure exerted by the gas is (B.H.U-94) (a) (b) (c) (d) Answer: (a) 21 The r.m.s velocity of oxygen molecules at 27°C is 318 m/s. the r.m.s velocity of hydrogen molecules at 127°C is (MHT-CET-2001) (a) 1470 m/s (b) 1603 m/s (c) 1869 m/s (d) 2240 m/s Answer: (a) 22 An ideal gas is that which can (MHT-CET-2001) (a) Be solidified (b) Liquefied (c) Not be liquefied (d) Not be solidified Answer: (c) 23 Following gases are kept at the same temperature. Which gas possesses maximum r.m.s. speed? (a) Oxygen (b) Nitrogen (c) Hydrogen (d) Carbon dioxide Answer: (c) 24 By what percentage should the pressure of a given mass of a gas be increased so as to decrease its volume by 10% at a constant temperature? (EAMCET-92) (a) 8.1% (b) 9.1% (c) 10.1% (d) 11.1% Answer: (d) 25 The gas expands adiabatically at constant pressure. Such that its temperature Tα the value of of the gas is (MHT-CET 2004) (a) 1.30 (b) 1.50 (c) 1.67 (d) 2.00 Answer: (b)