Class 11 Physics — Chapter 13: Kinetic Theory Online Test

1. The escape velocity from Earth is . At what temperature would rms velocity of hydrogen molecules equal escape velocity? M = 0.002 kg/mol.

2. Reynolds number is given by: Air () flows at velocity through a pipe of diameter . Calculate Reynolds number.

3. For a cylindrical pipe of length , inner radius , outer radius , and , temperature difference is . Calculate heat transfer per second.

4. If nitrogen gas has mean free path and average molecular speed , calculate diffusion coefficient.

5. If the enthalpy of vaporization of liquid helium at 4.2 K is , calculate the entropy change per mole during vaporization.

6. A 250 g block of ice at 0 °C is converted into water at 0 °C. Find the entropy change of the system. (, )

7. The macroscopic law is derived microscopically using:

8. Entropy () connects microscopic and macroscopic descriptions by the relation:

9. The Boltzmann constant () relates:

10. According to Arrhenius equation , how does temperature affect rate constant?

11. In chemical engineering, the diffusion coefficient for gases is often estimated using kinetic theory as:

12. Why is Brownian motion critical in nanomedicine for drug delivery systems?

13. According to Einstein’s 1905 explanation, the random motion of suspended particles in Brownian motion is caused by:

14. The mean free path is inversely proportional to:

15. A gas has . If 5 moles of this gas are heated at constant volume through 40 K, how much heat is absorbed?

16. The work done by an ideal gas in an isothermal process from to is:

17. According to the law of equipartition, the average energy per molecule of a monatomic ideal gas is:

18. For a monatomic ideal gas, the total average energy per molecule according to equipartition theorem is:

19. What happens to the pressure of a gas if the rms speed of its molecules doubles at constant volume?

20. Which formula relates pressure , number density , molecular mass , and mean square speed ?

1. White dwarfs in astrophysics are supported against gravitational collapse by:

2. For a gas mixture containing 1 mole of monatomic gas and 1 mole of diatomic gas (no vibrations), the effective molar is:

3. A gas effuses 1.414 times faster than oxygen. What is its molar mass?

4. According to kinetic theory, the volume of individual gas molecules compared to the total volume of the gas is:

5. Calculate the increase in internal energy when 4 moles of monatomic gas are heated by 50 K at constant volume.

6. What does the Maxwell-Boltzmann distribution describe in relation to thermodynamics?

7. In chemical engineering, the diffusion coefficient for gases is often estimated using kinetic theory as:

8. The Maxwell–Boltzmann distribution explains that:

9. Why is the factor of important in determining mean free path?

10. A metal rod of length , cross-sectional area , and thermal conductivity is subjected to a temperature difference of . Calculate heat current through the rod.

11. Rutherford’s alpha scattering experiment led to the conclusion that:

12. Why is mean free path important in determining thermal conductivity of gases?

13. The order of molecular speeds at a given temperature is:

14. In an experiment, the time of flow of 50 ml of a liquid through an Ostwald viscometer is 120 s, while that of water (viscosity = 0.001 Pa·s) is 100 s. If densities of the liquid and water are and respectively, calculate viscosity of the liquid.

15. A glass capillary has length , radius . Under a pressure head of of water (), water () flows through it. Calculate volume flow rate.

16. Using kinetic theory, show how viscosity relates to thermal conductivity . For monatomic gases: where is molar heat capacity at constant pressure. If for air and , calculate . (Molar volume at STP ).

17. Metallic bonds are best explained by which model?

18. Brownian motion decreases in intensity when:

19. Which of the following has the strongest intermolecular forces?

20. Why does Brownian motion become less visible in very viscous liquids like honey?

21. For a diatomic gas (ignoring vibrational energy), the molar heat capacity at constant volume is:

22. The Second Law of Thermodynamics states that entropy of an isolated system never decreases. How is this interpreted statistically?

23. Calculate the ratio of diffusion rates of helium (M = 4) and nitrogen (M = 28).

24. Which assumption of kinetic theory is violated when gases show liquefaction at high pressure?

25. Why does liquefaction of gases occur in real gases but not in ideal gases?

26. Which law can be derived from the kinetic theory assumption that average kinetic energy is proportional to absolute temperature?

27. Which type of intermolecular force is primarily responsible for the high boiling point of water?

28. According to Arrhenius equation , how does temperature affect rate constant?

29. Why does ice float on water, considering kinetic theory and molecular structure?

30. Which of the following does NOT affect the rate of a chemical reaction?

1. If a copper rod of cross-sectional area , length , and conducts of heat, what is the temperature difference across its ends?

2. Second-order (continuous) phase transitions are distinguished by:

3. In chemical reactors, gas mixing efficiency is strongly influenced by:

4. Why is viscosity critical in fluid engineering design?

5. The Maxwell–Boltzmann distribution provides a molecular basis for which thermodynamic law?

6. At what conditions do real gases behave most like ideal gases?

7. The ratio of rates of effusion of hydrogen and oxygen is:

8. Why do polyatomic gases generally have higher specific heat capacities than monatomic gases?

9. Which of the following is an example of an ionic bond?

10. The atomic number of an element represents:

11. Which ensemble is appropriate for systems with fixed energy, volume, and particle number?

12. In lubrication engineering, shear stress is given by Newton’s law: If oil film of viscosity and thickness separates two plates, one moving at , calculate shear stress.

13. In a viscometer test, water takes 90 s to flow through a tube, while a liquid of density takes 150 s. If viscosity of water is , find viscosity of liquid.

14. The mean free path for nitrogen at 300 K and 1 atm is . If viscosity , and is measured as , find approximate average molecular speed. Density .

15. According to Einstein’s 1905 explanation, the random motion of suspended particles in Brownian motion is caused by:

16. Which of the following is a characteristic property of metallic bonds?

17. The latent heat equation during condensation of a mass of vapor is:

18. What does the steric factor in collision theory account for?

19. According to the law of equipartition, the average energy per molecule of a monatomic ideal gas is:

20. According to kinetic theory, pressure of a gas arises due to:

21. In Hagen–Poiseuille flow, volumetric flow rate is: A liquid of viscosity flows through a tube of radius , length , under pressure difference . Calculate flow rate.

22. If 2 moles of water are vaporized at 100 °C and 1 atm, how much heat is absorbed? ()

23. Why do real gases deviate from ideal gas behavior at high pressure?

24. Brownian motion provides strong evidence for:

25. Which distribution describes the probability of molecular speeds in an ideal gas?

26. A gas mixture contains 2 moles of O and 4 moles of He at 300 K. Calculate ratio of rms speeds .

27. For a diatomic gas (ignoring vibrations), calculate the heat required to raise 2 moles of the gas by 40 K at constant volume.

28. A gas occupies 2 L at 300 K. If temperature is increased to 600 K at constant pressure, what is the new volume?

29. A balloon filled with air has a volume of 1.5 L at 27°C. What will be its volume at 127°C, if pressure remains constant?

30. Which of the following conditions increases the rate of diffusion of a gas?

31. A refrigerator extracts 200 kJ of heat from water at . How many grams of ice are formed? .

32. The mean free path of a gas molecule is related to number density and molecular diameter as:

33. In Stoke’s law method, the viscosity is given by: where is sphere radius, and are densities of sphere and fluid, is gravity, and is terminal velocity. A steel sphere of radius , density , falls in glycerin () with terminal velocity . Find .

34. Which equation derived by Einstein relates mean squared displacement in Brownian motion to time?

35. According to Charles’s law, if absolute temperature of a gas decreases, its volume:

36. Graham’s law of diffusion is consistent with kinetic theory because:

37. The failure of equipartition theorem at very low temperatures is explained by:

38. In particle physics, diffusion due to Brownian motion is important in gaseous detectors. The mean square displacement after time in 3D is:

39. What is the principal quantum number associated with?

40. Which of the following has metallic bonding?

41. If a wall of thickness and conductivity separates indoors at from outdoors at , calculate heat loss per square meter per second.

42. Why does ethanol () dissolve in water?

43. The average speed of molecules in Maxwell–Boltzmann distribution is:

44. A steel sphere of radius falls through oil of density . The sphere density is , terminal velocity . Find viscosity of oil.

45. For a cylindrical pipe of length , inner radius , outer radius , and , temperature difference is . Calculate heat transfer per second.

46. The root mean square displacement of a nanoparticle undergoing Brownian motion in time is given by:

47. Which fundamental quantity connects kinetic theory with thermodynamics?

48. In terms of kinetic theory, collision frequency () for two species is proportional to:

49. Why does the viscosity of gases increase with temperature, unlike liquids?

50. A cylinder contains 4 g of O gas at STP. Calculate average translational kinetic energy of all molecules together. (Avogadro’s number ).