NEET Thermodynamics — Set 25

Question 1

A system in a cyclic process absorbs $ 940 \, \text{J} $ of heat and rejects $ 360 \, \text{J} $. What is the net work done?

Accepted Answer

For cyclic: $ \Delta U = 0 $, $ Q_{\text{net}} = W $. $ Q_{\text{net}} = Q_{\text{absorb}} - Q_{\text{reject}} = 940 - 360 = 580 \, \text{J} $. $ W = 580 \, \text{J} $.

Question 2

Which of the following statements is incorrect regarding the Second Law of Thermodynamics?

Accepted Answer

The Second Law limits efficiency and directionality (e.g., no 100% heat-to-work conversion, Kelvin-Planck). Option B is incorrect; it contradicts the law, which requires heat rejection to a cold reservoir.

Question 3

Which of the following statements is correct regarding the Zeroth Law of Thermodynamics?

Accepted Answer

The Zeroth Law states that if two systems are in thermal equilibrium with a third, they are in equilibrium with each other, establishing temperature as a measurable property. It does not involve heat flow direction or work, which are addressed by other laws.

NEET Physics: Thermodynamics — Practice Set 25

Q1. A system in a cyclic process absorbs \( 940 \, \text{J} \) of heat and rejects \( 360 \, \text{J} \). What is the net work done?

Q2. Which of the following statements is incorrect regarding the Second Law of Thermodynamics?

Q3. Which of the following statements is correct regarding the Zeroth Law of Thermodynamics?

Q4. A gas expands adiabatically, doing 360 J of work. What is the change in its internal energy?

Q5. A gas expands adiabatically from \( 9 \, \text{atm} \) and \( 18 \, \text{L} \) to \( 3 \, \text{atm} \). What is the final volume? (\( \gamma = 1.4 \))

Q6. A monatomic gas undergoes an adiabatic expansion from \( 700 \, \text{K} \) to \( 350 \, \text{K} \) with \( 2 \, \text{moles} \). What is the work done? (\( R = 8.3 \, \text{J mol}^{-1} \text{K}^{-1} \), \( \gamma = 1.67 \))

Q7. What distinguishes work from heat as a mode of energy transfer?

Q8. A solid of \( 2 \, \text{moles} \) is heated from \( 300 \, \text{K} \) to \( 320 \, \text{K} \). If its molar specific heat capacity is \( 25.5 \, \text{J mol}^{-1} \text{K}^{-1} \), what is the heat supplied?

Q9. In an isobaric process, \( 1.2 \, \text{moles} \) of gas expand from \( 350 \, \text{K} \) to \( 420 \, \text{K} \). What is the heat supplied if \( C_p = 25.5 \, \text{J mol}^{-1} \text{K}^{-1} \)?

Q10. How much heat is required to vaporize \( 0.9 \, \text{g} \) of water at \( 100^\circ \text{C} \) and \( 1 \, \text{atm} \)? (Latent heat = \( 2256 \, \text{J/g} \))