A carnot engine is a device

Options

A. Which convert mechanical
energy into heat energy
B. Which convert heat energy into
mechanical energy
C. absorbs heat from a sink at a
lower temperature and rejects to the
source at high temperature
D. None of the above

Explanation

To solve the question regarding the Carnot engine, we need to understand its fundamental principles and operations. Here's a step-by-step breakdown of the solution:

### Step 1: Understand the Definition of a Carnot Engine
A Carnot engine is a theoretical thermodynamic cycle that provides the maximum possible efficiency for a heat engine. It operates between two heat reservoirs: a hot reservoir (source) and a cold reservoir (sink).

**Hint:** Remember that a Carnot engine operates between two temperatures: the higher temperature (TH) and the lower temperature (TL).

### Step 2: Identify the Function of the Carnot Engine
The primary function of a Carnot engine is to convert heat energy absorbed from a hot reservoir into mechanical work. It does this by absorbing heat (QH) from the hot reservoir and rejecting some of that heat (QL) to the cold reservoir.

**Hint:** Focus on the conversion process: heat energy (QH) is transformed into work (W).

### Step 3: Analyze the Options Given
1. **Option 1:** Converts mechanical energy into heat energy.
- This is incorrect as the Carnot engine does not convert mechanical energy into heat.

2. **Option 2:** Converts heat energy into mechanical energy.
- This is correct as the engine takes in heat from the hot reservoir and converts it into work.

3. **Option 3:** Absorbs heat from a sink at a lower temperature and rejects to the source at a higher temperature.
- This is incorrect. The Carnot engine absorbs heat from the hot reservoir (not the sink) and rejects heat to the cold reservoir (sink).

4. **Option 4:** None of the above.
- This is also incorrect since option 2 is a valid statement.

**Hint:** Evaluate each option based on the fundamental operation of the Carnot engine.

### Step 4: Conclusion
Based on the analysis of the options, the correct answer is **Option 2: which converts heat energy into mechanical energy**. This aligns with the definition and operation of a Carnot engine.

**Final Answer:** Option 2