Four slabs of iron heated to different temperatures show different colours listed below. The temperature is highest for

Options

A. yellow slab
B. red slab
C. white slab
D. green slab

Answer

To determine which of the four slabs of iron has the highest temperature based on their colors, we can use Wien's Displacement Law. This law states that the wavelength of the radiation emitted by a black body is inversely proportional to its temperature. Therefore, the color of the emitted light can give us an indication of the temperature of the slabs.

### Step-by-Step Solution:

1. **Identify the Colors and Corresponding Wavelengths**:
- The colors observed are yellow, red, white, and green.
- The order of colors from highest to lowest temperature based on their wavelengths is:
- White (shortest wavelength, highest temperature)
- Green
- Yellow
- Red (longest wavelength, lowest temperature)

2. **Apply Wien's Displacement Law**:
- According to Wien's Displacement Law, the temperature of an object is inversely related to the wavelength of the emitted radiation. This means that as the temperature increases, the wavelength decreases.

3. **Rank the Slabs Based on Color**:
- Since white light has the shortest wavelength, it corresponds to the highest temperature.
- Next is green, followed by yellow, and finally red, which has the longest wavelength and thus the lowest temperature.

4. **Conclusion**:
- Based on the analysis, the slab that is white has the highest temperature among the four slabs.

### Final Answer:
The temperature is highest for the white slab.

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