The instrument which is used for measuring the humidity of air is known as:

Options

A. hygrometer
B. potometer
C. auxanometer
D. psychrometer

Answer

To answer the question "The instrument which is used for measuring the humidity of air is known as:", we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Question**: The question asks for the name of the instrument used to measure humidity in the air.

2. **Review the Options**: The options provided are:
- A) Hygrometer
- B) Potometer
- C) Oxanometer
- D) Psychrometer

3. **Understand Each Instrument**:
- **Hygrometer**: This instrument is specifically designed to measure the moisture content or humidity in the air.
- **Potometer**: This device is used to measure the rate of water uptake by a plant and is not related to measuring humidity.
- **Oxanometer**: This instrument is used to measure the concentration of oxygen in a gas mixture, not humidity.
- **Psychrometer**: This is a type of hygrometer that uses two thermometers (wet bulb and dry bulb) to measure humidity, but it is a more specific type of hygrometer.

4. **Select the Correct Answer**: Based on the definitions and functions of the instruments, the correct answer is **Hygrometer** (Option A).

5. **Conclusion**: The instrument used for measuring the humidity of air is known as a **Hygrometer**.

### Final Answer:
The instrument which is used for measuring the humidity of air is known as a **Hygrometer**.

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