The instrument used to measure atmospheric pressure is____

Explanation

**Step-by-Step Solution:**

1. **Understanding Atmospheric Pressure**: Atmospheric pressure is the force exerted by the weight of air above a surface. It is an important concept in physics and meteorology.

2. **Identifying the Instrument**: To measure atmospheric pressure, we need a specific instrument. The commonly used instrument for this purpose is known as a barometer.

3. **Types of Barometers**: There are different types of barometers, but the most common ones are:
- Mercury Barometer: Uses mercury in a glass tube to measure atmospheric pressure.
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