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. If the pressure of a gas is reduced to half at constant temperature, what happens to mean free path?

2. The connection between partition function and Helmholtz free energy is:

3. The order parameter in phase transitions represents:

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

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

6. Show that viscosity of gases is nearly independent of pressure. For nitrogen at STP, mean free path . Using , explain why pressure cancels out.

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

8. Catalysts are essential in catalytic converters because they:

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

10. Which type of bond explains the malleability and ductility of metals?

11. Who was the first scientist to propose that matter is made up of indivisible particles called “atoms”?

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

13. In engineering insulation problems, effective thermal conductivity for multilayer walls is found by:

14. Which experimental observation best supports Avogadro’s law?

15. In terms of Helmholtz free energy , entropy is calculated as:

16. At 373 K, the enthalpy of vaporization of water is . Using Clausius–Clapeyron, calculate at 1 atm ().

17. A gas has a volume of 500 mL at 20°C. What will be its volume at 0°C at constant pressure?

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

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

20. A balloon at constant pressure shrinks in volume when cooled. Which molecular explanation fits Charles’s law?

21. A gas has a pressure of 5 atm when its volume is 10 L. What will be the pressure if the gas is compressed to 2 L at constant temperature?

22. If the diameter of molecules is halved while keeping pressure and temperature constant, the mean free path will:

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

24. The relation between average kinetic energy per molecule and temperature is:

25. Which of the following is an example of a metallic bond with a practical application?

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

27. The ensemble average of a physical quantity is mathematically defined as:

28. Which atmospheric phenomenon is best explained by gas diffusion and kinetic theory?

29. Which term in the Van der Waals equation accounts for molecular attractions?

30. Which transport property of gases is NOT directly related to mean free path?

1. An engine cylinder wall has area , thickness , and conductivity . If the inner wall is at and the outer at , calculate heat loss per second.

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

3. Which principle is used in designing catalytic converters for automobiles?

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

5. For an ideal gas, the relation between and is given by:

6. Which type of bond explains the malleability and ductility of metals?

7. Calculate the amount of heat required to melt 500 g of ice at . Latent heat of fusion of ice .

8. According to equipartition theorem, what is the molar heat capacity at constant pressure () for a monatomic ideal gas?

9. The Maxwell–Boltzmann distribution describes:

10. At very high pressure, which effect dominates the deviation from ideal gas behavior?

11. If air at STP has molecular diameter and number density , calculate mean free path.

12. The experimental fact that of solids approaches zero at very low temperatures is explained by:

13. In an adiabatic expansion of 2 moles of a monatomic gas from 5 L to 20 L at 300 K, the final temperature is approximately:

14. In statistical mechanics, the partition function is important because:

15. For 1 mole of diatomic gas (without vibrations), the molar heat capacity at constant pressure is:

16. According to kinetic theory, the pressure exerted by a gas in a container is due to:

17. A poor conductor of thickness and area allows of heat flow when the temperature difference across it is . Calculate its thermal conductivity.

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

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

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

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

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

23. For a diatomic gas at room temperature, neglecting vibrations, the molar predicted by equipartition theorem is:

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

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

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

27. Specific heat capacity is related to microscopic states because:

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

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

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

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

32. Metallic bonds are best explained by which model?

33. In statistical mechanics, first-order phase transitions are characterized by:

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

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

36. Which microscopic property determines diffusion rate of gases?

37. For an ideal gas, internal energy can be expressed in terms of partition function as:

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

39. Isotopes of an element have:

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

41. A balloon at constant pressure shrinks in volume when cooled. Which molecular explanation fits Charles’s law?

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

43. Which of the following is a basic assumption of the kinetic theory of gases?

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

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

46. Catalysts are essential in catalytic converters because they:

47. At STP, calculate collision frequency of oxygen molecules. Take .

48. The Clausius–Clapeyron equation for vaporization is:

49. Why is viscosity critical in fluid engineering design?

50. The density of a gas at STP can be calculated using Avogadro’s law and molar mass. Which is the formula?