Tea placed in thermos flask is an example of

Options

A. Open system
B. Close system
C. Isolated system
D. It can't act as system

Answer

To determine the type of thermodynamic system represented by tea placed in a thermos flask, we can analyze the characteristics of different systems: open, closed, and isolated systems.

### Step-by-Step Solution:

1. **Define the Types of Systems:**
- **Open System:** In an open system, both matter and energy can be exchanged with the surroundings. For example, a pot of boiling water where steam can escape and heat can be lost to the environment.
- **Closed System:** In a closed system, only energy can be exchanged with the surroundings, but matter cannot. An example is a sealed container of gas that can exchange heat with its environment but does not allow gas to escape.
- **Isolated System:** In an isolated system, neither matter nor energy can be exchanged with the surroundings. An example is a perfectly insulated container where no heat or matter can enter or leave.

2. **Analyze the Thermos Flask:**
- A thermos flask is designed to minimize heat exchange with the environment. It has insulation that prevents heat loss, thus keeping the contents hot for an extended period.
- When tea is placed in a thermos flask, it does not lose heat to the surroundings, and no matter (the tea itself) is exchanged with the environment.

3. **Conclusion:**
- Since the tea in the thermos flask does not exchange heat (energy) or matter with the surroundings, it is best described as an **isolated system**.

### Final Answer:
The tea placed in a thermos flask is an example of an **isolated system**.

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