Isothermal and adiabatic processes - Question Bank

1. An ideal gas is compressed rapidly. This process is best described as:
A) Isothermal, because the temperature is maintained.
B) Adiabatic, because there is little time for heat exchange.
C) Isobaric, because the pressure is constant.
D) Isochoric, because the volume is constant.
2. Which of the following is true for any process involving an ideal gas?
A) ΔU = nCvΔT
B) ΔU = nCpΔT
C) ΔU = Q
D) ΔU = -W
3. For a gas obeying PV^gamma = constant, if the initial temperature is T1 and final temperature is T2, then T1 * V1^(gamma-1) = T2 * V2^(gamma-1). This relationship is characteristic of which process?
A) Isothermal
B) Adiabatic
C) Isobaric
D) Isochoric
4. The condition Q=0 defines a process as:
A) Isothermal
B) Isobaric
C) Isochoric
D) Adiabatic
5. Which process involves the least amount of heat absorbed by a gas during expansion from state A to state B (where B is at lower pressure and higher volume than A)?
A) Adiabatic expansion
B) Isothermal expansion
C) Isobaric expansion
D) Isochoric expansion
6. Which process involves the largest amount of heat absorbed by a gas during expansion from state A to state B (where B is at lower pressure and higher volume than A)?
A) Adiabatic expansion
B) Isothermal expansion
C) Isobaric expansion
D) Isochoric expansion
7. In an adiabatic process involving an ideal gas, if the temperature doubles, the volume changes by a factor of:
A) (1/2)^(1/(gamma-1))
B) (1/2)^((gamma-1))
C) 2^(1/(gamma-1))
D) 2^((gamma-1))
8. When an ideal gas expands isothermally, the work done per mole is given by:
A) RT ln(V2/V1)
B) RT ln(P1/P2)
C) Cv(T2-T1)
D) Cp(T2-T1)
9. Which of the following is true for a system undergoing a reversible isothermal process where heat is added?
A) ΔU > 0, W > 0
B) ΔU = 0, Q = W
C) ΔU < 0, W < 0
D) Q = 0, W = 0
10. For an adiabatic process, T * V^(gamma-1) is:
A) Constant
B) Zero
C) Increases
D) Decreases
11. If a gas expands adiabatically, the work done is positive. This means the internal energy of the gas:
A) Increases
B) Decreases
C) Remains constant
D) Becomes zero
12. The specific heat capacity of an ideal gas in an isothermal process is:
A) Zero
B) Infinite
C) Cv
D) Cp
13. In a rapid compression of a gas in a cylinder, the process is best approximated as:
A) Isothermal
B) Isobaric
C) Adiabatic
D) Isochoric
14. For a given change in volume, which process involves more work done by the gas: isothermal expansion or adiabatic expansion?
A) Adiabatic expansion
B) Isothermal expansion
C) Work done is equal in both
D) Depends on the initial pressure
15. Which of the following is a characteristic of an isothermal compression?
A) Temperature increases, heat is absorbed.
B) Temperature remains constant, heat is released.
C) Temperature decreases, heat is released.
D) Temperature remains constant, heat is absorbed.
16. If an ideal gas is heated at constant volume (isochoric process), the work done is:
A) Positive
B) Negative
C) Zero
D) Depends on gamma
17. The equation PV^gamma = constant for an adiabatic process is derived from:
A) First Law of Thermodynamics and dQ=0
B) First Law of Thermodynamics and dU=0
C) Ideal Gas Law and dQ=0
D) Ideal Gas Law and dU=0
18. In an adiabatic expansion of a fixed amount of an ideal gas, the product PV:
A) Increases
B) Decreases
C) Remains constant
D) May increase or decrease
19. Which of the following is a necessary condition for an isothermal process to occur?
A) Perfect insulation
B) Very slow process
C) Sudden change in volume
D) Constant pressure
20. If an ideal gas expands isothermally, the work done is equal to:
A) The decrease in internal energy.
B) The heat absorbed by the gas.
C) The increase in internal energy.
D) Zero.
21. For a reversible adiabatic process, dQ = 0. According to the first law of thermodynamics, what does this imply?
A) dU = dW
B) dU = -dW
C) dU = 0
D) dW = 0
22. Which process is characterized by constant entropy?
A) Isothermal
B) Adiabatic
C) Isobaric
D) Isochoric
23. A quantity of gas is compressed adiabatically. Its temperature will:
A) Increase
B) Decrease
C) Remain the same
D) Become zero
24. The work done by a system during an isothermal process is always positive if:
A) The gas is compressed.
B) The gas is expanded.
C) The temperature is decreasing.
D) The pressure is constant.
25. Which of the following statements is INCORRECT for an adiabatic process?
A) Heat exchange with surroundings is zero.
B) Internal energy change is equal to the negative of work done.
C) Temperature remains constant.
D) PV^gamma = constant holds true.
26. In an isothermal process of an ideal gas, if the volume is doubled, the pressure becomes:
A) Half
B) Double
C) One-fourth
D) Four times
27. What is the work done in an adiabatic process when a gas expands from volume V1 to V2?
A) nRT ln(V2/V1)
B) (P1V1 - P2V2) / (gamma - 1)
C) P(V2-V1)
D) nCv(T2-T1)
28. If a gas undergoes an adiabatic process, the P-V curve is steeper than the P-V curve for an isothermal process. This is because:
A) Gamma (γ) is greater than 1.
B) Gamma (γ) is less than 1.
C) Temperature changes in adiabatic process.
D) Heat exchange occurs in adiabatic process.
29. If a gas undergoes an isothermal process, the P-V curve is a:
A) Straight line
B) Hyperbola
C) Parabola
D) Exponential curve
30. For a monatomic ideal gas, what is the value of gamma (γ)?
A) 1.40
B) 1.67
C) 1.33
D) 1.20
31. For a diatomic ideal gas, what is the value of gamma (γ)?
A) 1.40
B) 1.67
C) 1.33
D) 1.20
32. Which thermodynamic process is most closely approximated by the rapid expansion or compression of a gas in an insulated container?
A) Isothermal
B) Isochoric
C) Isobaric
D) Adiabatic
33. A process where heat can flow between the system and surroundings is called:
A) Adiabatic
B) Isothermal
C) Isobaric
D) Diathermic
34. Consider an ideal gas undergoing an adiabatic process. If its volume is doubled, what happens to its pressure?
A) It decreases to less than half.
B) It decreases to exactly half.
C) It decreases to more than half but less than one-fourth.
D) It decreases to one-fourth.
35. In a reversible adiabatic process for an ideal gas, the ratio of the change in temperature to the change in volume is proportional to:
A) (V/T)
B) (T/V)
C) (V^(gamma-1)/T)
D) (T/V^(gamma-1))
36. Which of the following represents the work done during an isothermal expansion of an ideal gas from volume V1 to V2 at temperature T?
A) nRT ln(V2/V1)
B) nCv(T2-T1)
C) P(V2-V1)
D) nCp(T2-T1)
37. For an isothermal process, the first law of thermodynamics (ΔU = Q - W) simplifies to:
A) ΔU = 0
B) Q = 0
C) Q = W
D) W = 0
38. In an adiabatic process, the change in internal energy (ΔU) is equal to:
A) Heat added (Q)
B) Work done (W)
C) -Work done (-W)
D) Zero
39. Which process is typically faster: isothermal or adiabatic?
A) Isothermal, because heat can be exchanged easily.
B) Adiabatic, because there is no heat exchange.
C) Both take the same time.
D) It depends on the gas.
40. During an adiabatic expansion of a gas, work is done by the gas. According to the first law of thermodynamics, this work is done at the expense of:
A) Heat absorbed from the surroundings
B) The gas's internal energy
C) The potential energy of the gas molecules
D) The kinetic energy of the surroundings
41. If an ideal gas undergoes an adiabatic compression, its temperature:
A) Decreases
B) Increases
C) Remains constant
D) Becomes zero
42. What does the symbol 'gamma' (γ) represent in the adiabatic process equation PV^gamma = constant?
A) Ratio of specific heats (Cp/Cv)
B) Ratio of molar masses
C) Specific heat at constant volume (Cv)
D) Specific heat at constant pressure (Cp)
43. For an adiabatic process, the relationship between pressure (P) and volume (V) is given by:
A) PV = constant
B) PV^gamma = constant
C) P/V = constant
D) P^gamma * V = constant
44. In an adiabatic expansion of an ideal gas, the internal energy:
A) Increases
B) Decreases
C) Remains constant
D) Is zero
45. Which of the following is true for an adiabatic process?
A) The temperature of the system remains constant.
B) The volume of the system remains constant.
C) No heat is exchanged between the system and the surroundings.
D) The pressure of the system remains constant.
46. If an ideal gas is compressed isothermally, what happens to the heat exchanged?
A) Heat is absorbed by the gas.
B) Heat is released by the gas.
C) No heat is exchanged.
D) Heat exchange depends on the specific heat capacity.
47. What is the relationship between pressure (P) and volume (V) for an ideal gas undergoing an isothermal process?
A) PV = constant
B) P/V = constant
C) P + V = constant
D) PV^gamma = constant
48. Which law of thermodynamics is directly applied to an isothermal process involving an ideal gas?
A) Zeroth Law
B) First Law
C) Second Law
D) Third Law
49. For an isothermal expansion of an ideal gas, the work done by the gas is:
A) Zero
B) Positive
C) Negative
D) Equal to the heat absorbed
50. In an isothermal process, the internal energy of an ideal gas:
A) Increases
B) Decreases
C) Remains constant
D) Changes depending on the pressure
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