The thickness of ozone in the atmospheric layer is measured in :

Options

A. dB
B. atm
C. DU
D. ppm

Answer

To solve the question regarding the measurement of the thickness of ozone in the atmospheric layer, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Measurement Units**: The question asks about the units used to measure the thickness of ozone in the atmosphere. Common units of measurement include decibels (dB), atmospheres (atm), Dobson units (DU), and parts per million (ppm).

2. **Analyze Each Option**:
- **Decibel (dB)**: This unit measures sound intensity, not applicable to ozone thickness.
- **Atmosphere (atm)**: This unit measures pressure, not specifically related to the thickness of ozone.
- **Dobson Unit (DU)**: This unit is specifically designed to measure the thickness of the ozone layer. It was named after the scientist G.M.B. Dobson, who contributed significantly to the study of atmospheric ozone.
- **Parts Per Million (ppm)**: This unit is used to measure the concentration of small particles in a solution or mixture, not the thickness of a layer.

3. **Conclusion**: The correct unit for measuring the thickness of the ozone layer is the Dobson Unit (DU). The normal thickness of the ozone layer is often referred to as 300 DU.

### Final Answer:
The thickness of ozone in the atmospheric layer is measured in **Dobson Units (DU)**.

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