Physics-DPP-1-5.Thermometry, Thermal Expansion and Kinetic Theory of Gases

PHYSICS Topic: Thermometry, Thermal Expansion and Kinetic Theory of Gases Date: 1. Pressure versus temperature graph of an ideal gas at constant volume V is shown by the straight line A. Now mass of the gas is doubled and the volume is halved, then corresponding pressure versus temperature graph will be shown by the line: (a) A (b) B (c) C (d) none of these 2. A gas mixture consists of 2 moles of O2 and 4 moles of Ar at temperature T. Neglecting all vibrational modes, the total internal energy of the system is : (a) 4RT (b) 15RT (c) 9RT (d) 11RT 3. The specific heat, of the mixture of two gases, at constant volume is is 1 : 2. The respective gases may be : 13 6 R. The ratio of number of moles of the first gas to the second (a) O2, N2 (b) He, Ne (c) He, N2 (d) N2, He 4. A cylindrical steel plug is inserted into a circular hole of diameter 2.60 cm in a brass plate. When the plug and the plates are at a temperature of 200C, the diameter of the plug is 0.010 cm smaller than that of the hole. The temperature at which the plug will just fit in it is : çæ 11×10–6 19×10–6 ö÷ çGiven,αsteel = o and αbrass = o ÷ èç C C ø÷ (a) –480 C (b) –200 C (c) –100 C (d) –4580 C 5. The mass of hydrogen molecule is 3.32  10–27 kg. If 1023 hydrogen molecules strike per second at 2 cm2 area of a rigid wall at an angle of 450 from the normal and rebound back with a speed of 1000 m/s, then the pressure exerted on the wall is : (a) 2.34  103 Pa (b) 0.23  106 Pa (c) 0.23  103 Pa (d) 23.4  103 Pa 6. A ring shaped tube contains two ideal gases with equal masses and relative molar masses M1 = 32 and M2 = 28. The gases are separated by one fixed partition P and another movable stopper S which can move frelly without friction inside the ring. The angle  in equilibrium as shown in the figure (in degrees) is : (a) 291 (b) 219 (c) 129 (d) 192 7. A piece of metal weighs 46 g in air. When it is immersed liquid of specific gravity 1.24 at 270C, it weighs 30g. When the temperature is raised to 420C, the metal piece weighs 30.5 g. If the specific gravity of the liquid is 420C is 1.20, the coefficient of linear expansion of the metal is : (a) 1.4 × 10–5 0 C (b) 2.3 × 10–5 0 C (c) 4.3 × 10–5 0 C (d) 3.4 × 10–5 0 C PHYSICS Topic: Thermometry, Thermal Expansion and Kinetic Theory of Gases Date: 8. The apparent coefficient of expansion of a liquid when heated in a copper vessel is C and when heated in a silver vessel is S. If A is the linear coefficient of expansion of copper, then the linear coefficient of expansion of silver is : (a) C + S – 3A 3 (b) (b) C + 3A – S 3 (c) (c) S + 3A – C 3 (d) (d) C + S + 3A 3 9. Three rods of equal length l are joined to from an equilateral triangle PQR. O is the mid point of PQ. Distance OR remains same for small change in temperature. Coefficient of linear expansion for PR and RQ is same i.e.  but that for PQ is  . then : (a)  = 3 2 1 (b)    2 1   (c)    (d)    10. Pressure versus temperature graph of an ideal gas of equal number of moles of different volumes are plotted as shown in figure. Choose the correct alternative : (a) V1 = V2, V3 = V4 and V2 > V3 (b) V1 = V2, V3 = V4 and V2 < V3 (c) V1 = V2= V3 = V4 (d) V4 > V3 > V2 > V1 *** End of Paper *** PHYSICS Topic: Thermometry, Thermal Expansion and Kinetic Theory of Gases Date: Answer Key 1. (b) 2. (d) 3. (c) 4. (d) 5. (a) 6. (d) 7. (b) 8. (a) 9. (d) 10. (a)