Subtopic: Fundamentals of Biomolecules, enzyme kinetics
Question Statement:
Which one of the following statements is correct in the context of thermodynamics?
Options:
(A) In a closed system, neither mass nor energy is transferred across the system
boundary
(B) In a closed system, both mass and energy can be transferred across the system
boundary
(C) The total energy of the system is the sum of kinetic and potential energies
(D) In a closed system, only energy can be transferred across the system boundary and
not mass
Official Answer Key:
D
Step-by-Step Solution & Explanation
### **Official Solution & Concept Analysis (GATE BT 2024 Q.13)**
**1. Governing Concept**:
- **Topic**: Classical Thermodynamics & System Boundaries
- Thermodynamic system definitions:
- **Open system**: Both mass and energy can cross the system boundary.
- **Closed system**: Energy (heat and work) can cross the system boundary, but **mass cannot**.
- **Isolated system**: Neither mass nor energy can cross the boundary.
**2. Option Analysis**:
- **Option (A) is INCORRECT**: Describes an isolated system, not a closed system.
- **Option (B) is INCORRECT**: Describes an open system.
- **Option (C) is INCORRECT**: Total energy of a thermodynamic system includes internal energy ($U$) in addition to kinetic ($KE$) and potential ($PE$) energies ($E = U + KE + PE$).
- **Option (D) is CORRECT**: In a closed system, energy transfers across the boundary, but mass is strictly contained.
**3. Final Answer**:
- **Correct Choice**: **D**
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