A device used to measure very high temperature is

Options

A. pyrometer
B. Thermometer
C. Barometer
D. Calorimeter

Explanation

To solve the question "A device used to measure very high temperature is", we will analyze the options provided and identify the correct device.

### Step-by-Step Solution:

1. **Identify the Options**: The options given are:
- A) Parameter
- B) Barometer
- C) Calorimeter
- D) Thermometer

2. **Understand Each Device**:
- **Calorimeter**: This device is used to measure the amount of heat involved in chemical reactions or physical changes. It does not measure temperature directly.
- **Barometer**: This instrument measures atmospheric pressure, not temperature.
- **Thermometer**: This device measures temperature but is typically limited to measuring temperatures up to around 100 degrees Celsius (for liquid-in-glass thermometers).
- **Parameter**: This seems to be a typographical error in the options. The correct term should be "Pyrometer".

3. **Identify the Correct Device for High Temperatures**:
- Since the question specifically asks for a device that measures very high temperatures, we need to consider the appropriate instrument. The correct device for measuring very high temperatures is a **Pyrometer**. Pyrometers are designed to measure temperatures that exceed the limits of standard thermometers.

4. **Conclusion**: Based on the analysis, the device used to measure very high temperature is a **Pyrometer**.

### Final Answer:
The correct answer is **Pyrometer**.