Which of the follwing is NOT the use of polaroid ?

Options

A. LCD screen
B. Colour constrast
C. Control amount of light in aeroplne window
D. Vehicle side mirror

Answer

To determine which of the following is NOT a use of Polaroid, we will analyze each option provided:

1. **LCD Screen**: Polaroids are used in LCD screens to reduce glare and control the intensity of light. They help in polarizing the light, which enhances visibility and reduces reflections. Thus, this is a valid use of Polaroid.

2. **Color Contrast**: Polaroids are also used to improve color contrast. High-intensity light can wash out colors, making it difficult to distinguish between them. By using Polaroids, the intensity of light can be reduced, allowing for better color differentiation. This is another valid use of Polaroid.

3. **Control Amount of Light in Airplane Window**: Polaroids are used in airplane windows to control the amount of light entering the cockpit. This is crucial for pilots to avoid being blinded by bright light, thereby enhancing safety. This is a legitimate use of Polaroid.

4. **Vehicle Side Mirror**: Vehicle side mirrors typically use convex mirrors to provide a wider field of view. While some side mirrors may incorporate Polaroid technology to reduce glare, the primary function of side mirrors is not to reduce light intensity but to provide a broader view. Therefore, this option is not a primary use of Polaroid.

Based on the analysis, the option that is NOT a use of Polaroid is **Vehicle Side Mirror**.

### Step-by-Step Solution:
1. **Identify the options provided**: LCD Screen, Color Contrast, Control Amount of Light in Airplane Window, Vehicle Side Mirror.
2. **Evaluate the use of Polaroid in each option**:
- **LCD Screen**: Used to reduce glare and enhance visibility.
- **Color Contrast**: Improves the ability to distinguish colors by reducing light intensity.
- **Control Amount of Light in Airplane Window**: Essential for pilot safety by controlling brightness.
- **Vehicle Side Mirror**: Primarily uses convex mirrors; Polaroid is not a primary function.
3. **Determine which option does not align with the uses of Polaroid**: Vehicle Side Mirror is not primarily used for reducing light intensity.
4. **Conclude the answer**: The option that is NOT a use of Polaroid is **Vehicle Side Mirror**.