NEET Thermodynamics — Set 3

Question 1

Which of the following statements correctly defines thermal equilibrium?

Accepted Answer

Thermal equilibrium occurs when two systems in contact have no net heat flow between them, indicating equal temperatures, as per the Zeroth Law. Option C is correct.

Question 2

In an isobaric process, $ 1.6 \, \text{moles} $ of an ideal gas expand from $ 6 \, \text{L} $ to $ 12 \, \text{L} $ at $ 400 \, \text{K} $. What is the work done by the gas? ($ R = 8.3 \, \text{J mol}^{-1} \text{K}^{-1} $)

Accepted Answer

$ W = P \Delta V $, $ P V = \mu R T $. $ \Delta V = 12 - 6 = 6 \, \text{L} $. $ P = \frac{\mu R T}{V_1} = \frac{1.6 \times 8.3 \times 400}{6} = 885.33 \, \text{atm} $ (unit correction needed). Directly: $ W = \mu R T \left(\frac{V_2 - V_1}{V_1}\right) $, but $ W = P \Delta V $. $ W = 1.6 \times 8.3 \times 400 = 5312 \, \text{J} $ (adjusted).

Question 3

In an isobaric process, $ 1.2 \, \text{moles} $ of gas expand from $ 340 \, \text{K} $ to $ 430 \, \text{K} $. What is the heat supplied if $ C_p = 24.9 \, \text{J mol}^{-1} \text{K}^{-1} $?

Accepted Answer

$ \Delta Q = \mu C_p \Delta T $. $ \mu = 1.2 $, $ C_p = 24.9 $, $ \Delta T = 430 - 340 = 90 $. $ \Delta Q = 1.2 \times 24.9 \times 90 = 2694.6 \, \text{J} \approx 2695 \, \text{J} $.

NEET Physics: Thermodynamics — Practice Set 3

Q1. Which of the following statements correctly defines thermal equilibrium?

Q2. In an isobaric process, \( 1.6 \, \text{moles} \) of an ideal gas expand from \( 6 \, \text{L} \) to \( 12 \, \text{L} \) at \( 400 \, \text{K} \). What is the work done by the gas? (\( R = 8.3 \, \text{J mol}^{-1} \text{K}^{-1} \))

Q3. In an isobaric process, \( 1.2 \, \text{moles} \) of gas expand from \( 340 \, \text{K} \) to \( 430 \, \text{K} \). What is the heat supplied if \( C_p = 24.9 \, \text{J mol}^{-1} \text{K}^{-1} \)?

Q4. A gas expands adiabatically from \( 4 \, \text{atm} \) and \( 8 \, \text{L} \) to \( 1 \, \text{atm} \). What is the final volume? (\( \gamma = 1.67 \))

Q5. A gas at \( 2 \, \text{atm} \) and \( 27^\circ \text{C} \) in a \( 5 \, \text{L} \) container is compressed isochorically until its pressure becomes \( 4 \, \text{atm} \). What is the final temperature?

Q6. In an adiabatic process, \( 1 \, \text{mole} \) of gas at \( 600 \, \text{K} \) does \( 2000 \, \text{J} \) of work. What is the final temperature? (\( \gamma = 1.4 \), \( R = 8.3 \, \text{J mol}^{-1} \text{K}^{-1} \))

Q7. In an isobaric process, what remains constant?

Q8. Which of the following statements is correct about a quasi-static process?

Q9. A gas undergoes an adiabatic compression from \( 16 \, \text{L} \) to \( 4 \, \text{L} \), increasing its pressure from \( 1 \, \text{atm} \) to \( 8 \, \text{atm} \). What is the value of \( \gamma \)?

Q10. Which of the following is NOT a requirement for the Zeroth Law to apply?

Q11. What prevents a spontaneous process like free expansion from being reversible?

Q12. What is the change in internal energy for \( 0.7 \, \text{moles} \) of an ideal gas heated from \( 280 \, \text{K} \) to \( 340 \, \text{K} \) at constant volume? (\( C_v = 20.8 \, \text{J mol}^{-1} \text{K}^{-1} \))

Q13. Which of the following statements is correct about heat in thermodynamics?

Q14. Why does the Second Law impose a limit on the efficiency of a heat engine?