A thermally isolated gaseous system can exchange energy with the surroundings. The mode of energy may be

Options

A. Heat
B. Work
C. Heat and radiation
D. Internal energy

Answer

To solve the question regarding the energy exchange in a thermally isolated gaseous system, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of a Thermally Isolated System**:
A thermally isolated system is one that does not exchange heat or matter with its surroundings. This means that there is no transfer of thermal energy (heat) between the system and the environment.

**Hint**: Remember that "thermally isolated" implies no heat transfer.

2. **Identify the Modes of Energy Transfer**:
In thermodynamics, energy can be transferred in two primary ways: as heat or as work. Since we are dealing with a thermally isolated system, heat transfer is not possible.

**Hint**: Recall the two main forms of energy transfer in thermodynamics: heat and work.

3. **Determine the Possible Energy Changes**:
Although heat cannot be exchanged, the internal energy of the system can still change. This change can occur through work done on or by the system. Work can be performed by the system as it expands or is compressed, or work can be done on the system.

**Hint**: Think about how work can affect the internal energy of a system without involving heat transfer.

4. **Conclude the Mode of Energy Exchange**:
Since the system is thermally isolated and cannot exchange heat, the only mode of energy transfer that can occur is through work. Therefore, the internal energy of the system can change due to work done.

**Hint**: Focus on the fact that work is the only form of energy transfer available in a thermally isolated system.

5. **Final Answer**:
The mode of energy exchange in a thermally isolated gaseous system is **work**.

### Summary:
The correct answer to the question is that the mode of energy exchange in a thermally isolated gaseous system is **work**. Heat transfer is not possible, and other forms of energy transfer like radiation do not apply in this context.