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

2. Why do reactions between ions in aqueous solution usually occur very fast?

3. Which of the following best demonstrates Boyle’s law in real life?

4. According to Bohr’s model, the angular momentum of an electron in orbit is quantized as:

5. For water at 1 atm, the enthalpy of vaporization is approximately . Calculate the heat needed to vaporize 18 g (1 mol) of water.

6. Which of the following gases has the largest Van der Waals constant ?

7. Which law of thermodynamics is consistent with the conservation of molecular kinetic energy in elastic collisions?

8. The specific heat capacity at constant volume of an ideal gas can be calculated using:

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

10. A 100 nm gold nanoparticle in water has . What is its root mean square displacement in 1 second?

11. Which of the following best describes dipole–dipole forces?

12. The mean kinetic energy of one mole of an ideal gas at temperature is:

13. If the probability distribution of a quantity is sharply peaked, what does it imply about fluctuations?

14. How does kinetic theory explain the pressure exerted by liquids in a container?

15. The use of catalysts in chemical kinetics primarily affects:

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

17. In Poiseuille’s method, if radius of capillary is doubled, volume flow rate of liquid changes by a factor of:

18. What is the primary reason ionic compounds conduct electricity in molten state but not in solid state?

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

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

21. The rate of effusion of a gas through a small hole is proportional to:

22. Why must Charles’s law be expressed in Kelvin instead of Celsius?

23. The mean free path of air molecules at 1 atm is . What will it be at pressure of , at same temperature?

24. Einstein’s expression for the diffusion coefficient of spherical particles of radius suspended in a fluid of viscosity is:

25. If a sealed syringe containing 30 mL of air at 1 atm is compressed to 10 mL without changing temperature, what is the final pressure?

26. Which type of bonding explains why aluminum is both strong and a good conductor of electricity?

27. Which scientist is credited with formulating Avogadro’s law?

28. In kinetic theory derivation, the temperature of a gas is defined in terms of:

29. Isotopes of an element have:

30. The critical temperature of a gas is defined as:

1. In statistical mechanics, entropy is expressed as:

2. Which scientist provided the first clear statement that gas pressure is due to molecular collisions?

3. The equation was used by Jean Perrin to:

4. The Gibbs free energy change for a first-order phase transition is:

5. A furnace wall of thickness , area , conductivity , has inside , outside . Calculate heat loss per second.

6. In astrophysics, critical opalescence near phase transitions occurs because:

7. For a diatomic molecule (ignoring vibrational modes), how many degrees of freedom are considered in equipartition theorem?

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

9. How does temperature affect the mean free path at constant pressure?

10. 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 .

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

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

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

14. Why does sodium chloride (NaCl) have a high melting point?

15. Which property of liquids is most influenced by intermolecular forces?

16. The ratio of specific heats () for a diatomic gas at moderate temperature is approximately:

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

18. A vessel contains helium at 300 K and pressure . If average kinetic energy per atom = , calculate energy of 1 mole.

19. Which thermodynamic process involves heat transfer but no change in temperature?

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

21. The specific heat ratio can be determined experimentally by:

22. Which statistical distribution applies to indistinguishable particles with half-integer spin (electrons, protons, neutrons)?

23. What role did Einstein’s theory of Brownian motion play in physics history?

24. The ideal gas equation is consistent with kinetic theory because:

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

26. Which of the following quantities is NOT directly needed to calculate mean free path?

27. Calculate the internal energy of 2 moles of a monatomic ideal gas at 300 K.

28. Which of the following compounds has a purely covalent bond?

29. Which of the following speeds is NOT defined in the context of Maxwell–Boltzmann distribution?

30. The specific heat capacity at constant volume of an ideal gas can be calculated using:

31. A sample of oxygen () is at 300 K. Calculate its rms speed.

32. Why is measuring viscosity important in engineering applications?

33. Why do liquids evaporate even at room temperature?

34. Calculate most probable speed of hydrogen molecules at 300 K:

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

36. Brownian motion decreases in intensity when:

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

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

39. For oxygen gas at 300 K, molar mass . Calculate rms speed and then viscosity using . Given , , .

40. If the pressure of a gas is kept constant and the temperature is doubled, what happens to the mean free path?

41. In probability distributions, the normalization condition requires:

42. A sample of gas has a volume of 250 mL at 300 K. To maintain constant pressure, what temperature is needed for the volume to expand to 500 mL?

43. Why does statistical mechanics predict universality near critical points?

44. The molar heat capacity at constant volume, , for a diatomic gas (ignoring vibrations) is:

45. Which scientist first published the law of pressure-volume relationship (Boyle’s law)?

46. Diffusion of gases is defined as:

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

48. The specific heat at constant volume of 1 mole of an ideal monatomic gas is:

49. Which of the following is NOT true for covalent bonds?

50. How does kinetic theory help explain the states of matter?