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. Thermal conductivity () of a material is defined by Fourier’s law of heat conduction:

2. According to Graham’s law, the rate of diffusion or effusion is:

3. The law of equipartition of energy states that:

4. At a liquid–gas critical point, the order parameter vanishes. If density difference between phases is , then near critical temperature:

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

6. The mean free path of a gas molecule is defined as:

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

8. The order parameter in phase transitions represents:

9. In molecular dynamics simulations, why is mean free path important?

10. Temperature is directly related to which microscopic property of molecules?

11. The equation was used by Jean Perrin to:

12. The heat flux through a wall is found experimentally to be for a temperature difference of across . Calculate thermal conductivity.

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

14. For a lubricant in a bearing, power lost due to viscous drag is: If shear stress , area , velocity , calculate power loss.

15. Which of the following is NOT an assumption of kinetic theory?

16. A triatomic linear molecule like has how many degrees of freedom (ignoring vibrations)?

17. Which microscopic property determines diffusion rate of gases?

18. Which of the following explains why iodine () is solid at room temperature while chlorine () is a gas?

19. According to kinetic theory, viscosity of a gas is given by where is density, is average molecular speed, and is mean free path. If air has , , and , calculate .

20. The molar specific heat at constant volume is defined as:

21. According to kinetic theory, the distribution of molecular speeds in a gas:

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

23. The mean free path is inversely proportional to:

24. Why do smaller suspended particles show more vigorous Brownian motion compared to larger ones?

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

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

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

28. If a gas occupies 4 L at 2 atm pressure, what volume will it occupy at 1 atm, assuming constant temperature?

29. The molar volume of an ideal gas at STP (Standard Temperature and Pressure, 273 K and 1 atm) is:

30. In the contact process for sulfuric acid production, which catalyst is used?

1. 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.

2. The molecular speed distribution widens when:

3. Why does viscosity of the medium affect Brownian motion?

4. In nuclear emulsions, Brownian-like motion of ions can be modeled using which formula?

5. Joule’s contribution to kinetic theory was primarily through:

6. Which equation links diffusion coefficient of nanoparticles to temperature, radius, and viscosity, and is used in nanotechnology research?

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

8. In statistical mechanics, entropy is expressed as:

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

10. For 1 mole of a monatomic gas at temperature , the total internal energy is:

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

12. Which scientist’s work finally unified the microscopic kinetic theory with macroscopic thermodynamics?

13. Why does heat conduction occur in gases according to kinetic theory?

14. At 300 K, calculate fraction of nitrogen molecules with speed greater than 1000 m/s using Maxwell–Boltzmann distribution: M = 0.028 kg/mol.

15. Which property of water is NOT directly explained by hydrogen bonding?

16. The average energy per molecule of a diatomic gas at moderate temperatures (ignoring vibrations) is:

17. Calculate most probable speed of O molecules at 500 K:

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

19. Calculate the heat required to raise the temperature of 3 moles of a diatomic gas (ignoring vibrations) by 50 K at constant pressure.

20. A glass window area, thick, with separates inside and outside . Calculate heat loss per second.

21. Which of the following correctly represents root mean square (rms) speed?

22. In the Maxwell–Boltzmann speed distribution curve, the area under the curve represents:

23. In Lee’s disc experiment, if brass disc of heat capacity cools at , calculate heat flow through the sample.

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

25. The difference between molar heat capacities at constant pressure and volume is:

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

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

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

29. Which compound is held together by covalent bonding?

30. If a gas occupies 4 L at 2 atm pressure, what volume will it occupy at 1 atm, assuming constant temperature?

31. The probability distribution of molecular speeds in a gas is given by:

32. How does the presence of a catalyst affect the reaction rate?

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

34. Which of the following is a property of covalent compounds?

35. Which of the following explains why carbon dioxide liquefies more easily than oxygen?

36. Which scientist discovered the relationship now known as Charles’s law?

37. Which of the following is the correct order of characteristic molecular speeds?

38. Avogadro’s law provides direct evidence for which concept?

39. Which factor does NOT affect collision frequency?

40. According to kinetic theory, the distribution of molecular speeds in a gas:

41. Metallic bonds are best explained by which model?

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

43. How does pressure affect the mean free path of a gas?

44. Which ensemble is used for a system at fixed temperature, volume, and chemical potential (allowing particle exchange)?

45. In statistical mechanics, an ensemble refers to:

46. A superconductor undergoes a second-order phase transition at critical temperature . The specific heat shows:

47. In the derivation of gas pressure, why is the factor included?

48. Pressure affects the rate of reaction most strongly in:

49. Kinetic theory assumes that collisions between gas molecules are:

50. The latent heat of fusion of ice is . How much ice at 0 °C can be melted with 100 kJ of heat?