The length of a piece of wood is measured with a metallic scale on a hot day. The measured value will be

Options

A. more than original value
B. less than original value
C. equal to original value
D. can't predict

Explanation

To solve the question regarding the measurement of the length of a piece of wood with a metallic scale on a hot day, we need to consider the effects of temperature on both the wood and the metallic scale.

### Step-by-Step Solution:

1. **Understand Thermal Expansion**:
- Both the metallic scale and the wooden piece will expand when the temperature increases. This is known as thermal expansion.

2. **Effect on the Metallic Scale**:
- The metallic scale, being made of metal, will expand more than the wood. This means that the measuring units on the scale will also become longer.

3. **Effect on the Wooden Piece**:
- The wooden piece will also expand, but typically, wood expands less than metal. Therefore, the actual length of the wood will increase, but not as much as the scale.

4. **Comparison of Expansion**:
- Since the metallic scale expands more than the wooden piece, the scale will show a longer measurement than the actual length of the wood.

5. **Conclusion**:
- As a result, when measuring the length of the wood with the metallic scale on a hot day, the measured value will be **greater than the actual length of the wood**.

### Final Answer:
The measured value will be greater than the actual length of the piece of wood.

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